113481Sgiacomo.travaglini@arm.com 213481Sgiacomo.travaglini@arm.com 313481Sgiacomo.travaglini@arm.comNow that you have read [Primer](V1_7_Primer.md) and learned how to write tests 413481Sgiacomo.travaglini@arm.comusing Google Test, it's time to learn some new tricks. This document 513481Sgiacomo.travaglini@arm.comwill show you more assertions as well as how to construct complex 613481Sgiacomo.travaglini@arm.comfailure messages, propagate fatal failures, reuse and speed up your 713481Sgiacomo.travaglini@arm.comtest fixtures, and use various flags with your tests. 813481Sgiacomo.travaglini@arm.com 913481Sgiacomo.travaglini@arm.com# More Assertions # 1013481Sgiacomo.travaglini@arm.com 1113481Sgiacomo.travaglini@arm.comThis section covers some less frequently used, but still significant, 1213481Sgiacomo.travaglini@arm.comassertions. 1313481Sgiacomo.travaglini@arm.com 1413481Sgiacomo.travaglini@arm.com## Explicit Success and Failure ## 1513481Sgiacomo.travaglini@arm.com 1613481Sgiacomo.travaglini@arm.comThese three assertions do not actually test a value or expression. Instead, 1713481Sgiacomo.travaglini@arm.comthey generate a success or failure directly. Like the macros that actually 1813481Sgiacomo.travaglini@arm.comperform a test, you may stream a custom failure message into the them. 1913481Sgiacomo.travaglini@arm.com 2013481Sgiacomo.travaglini@arm.com| `SUCCEED();` | 2113481Sgiacomo.travaglini@arm.com|:-------------| 2213481Sgiacomo.travaglini@arm.com 2313481Sgiacomo.travaglini@arm.comGenerates a success. This does NOT make the overall test succeed. A test is 2413481Sgiacomo.travaglini@arm.comconsidered successful only if none of its assertions fail during its execution. 2513481Sgiacomo.travaglini@arm.com 2613481Sgiacomo.travaglini@arm.comNote: `SUCCEED()` is purely documentary and currently doesn't generate any 2713481Sgiacomo.travaglini@arm.comuser-visible output. However, we may add `SUCCEED()` messages to Google Test's 2813481Sgiacomo.travaglini@arm.comoutput in the future. 2913481Sgiacomo.travaglini@arm.com 3013481Sgiacomo.travaglini@arm.com| `FAIL();` | `ADD_FAILURE();` | `ADD_FAILURE_AT("`_file\_path_`", `_line\_number_`);` | 3113481Sgiacomo.travaglini@arm.com|:-----------|:-----------------|:------------------------------------------------------| 3213481Sgiacomo.travaglini@arm.com 3313481Sgiacomo.travaglini@arm.com`FAIL()` generates a fatal failure, while `ADD_FAILURE()` and `ADD_FAILURE_AT()` generate a nonfatal 3413481Sgiacomo.travaglini@arm.comfailure. These are useful when control flow, rather than a Boolean expression, 3513481Sgiacomo.travaglini@arm.comdeteremines the test's success or failure. For example, you might want to write 3613481Sgiacomo.travaglini@arm.comsomething like: 3713481Sgiacomo.travaglini@arm.com 3813481Sgiacomo.travaglini@arm.com``` 3913481Sgiacomo.travaglini@arm.comswitch(expression) { 4013481Sgiacomo.travaglini@arm.com case 1: ... some checks ... 4113481Sgiacomo.travaglini@arm.com case 2: ... some other checks 4213481Sgiacomo.travaglini@arm.com ... 4313481Sgiacomo.travaglini@arm.com default: FAIL() << "We shouldn't get here."; 4413481Sgiacomo.travaglini@arm.com} 4513481Sgiacomo.travaglini@arm.com``` 4613481Sgiacomo.travaglini@arm.com 4713481Sgiacomo.travaglini@arm.com_Availability_: Linux, Windows, Mac. 4813481Sgiacomo.travaglini@arm.com 4913481Sgiacomo.travaglini@arm.com## Exception Assertions ## 5013481Sgiacomo.travaglini@arm.com 5113481Sgiacomo.travaglini@arm.comThese are for verifying that a piece of code throws (or does not 5213481Sgiacomo.travaglini@arm.comthrow) an exception of the given type: 5313481Sgiacomo.travaglini@arm.com 5413481Sgiacomo.travaglini@arm.com| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | 5513481Sgiacomo.travaglini@arm.com|:--------------------|:-----------------------|:-------------| 5613481Sgiacomo.travaglini@arm.com| `ASSERT_THROW(`_statement_, _exception\_type_`);` | `EXPECT_THROW(`_statement_, _exception\_type_`);` | _statement_ throws an exception of the given type | 5713481Sgiacomo.travaglini@arm.com| `ASSERT_ANY_THROW(`_statement_`);` | `EXPECT_ANY_THROW(`_statement_`);` | _statement_ throws an exception of any type | 5813481Sgiacomo.travaglini@arm.com| `ASSERT_NO_THROW(`_statement_`);` | `EXPECT_NO_THROW(`_statement_`);` | _statement_ doesn't throw any exception | 5913481Sgiacomo.travaglini@arm.com 6013481Sgiacomo.travaglini@arm.comExamples: 6113481Sgiacomo.travaglini@arm.com 6213481Sgiacomo.travaglini@arm.com``` 6313481Sgiacomo.travaglini@arm.comASSERT_THROW(Foo(5), bar_exception); 6413481Sgiacomo.travaglini@arm.com 6513481Sgiacomo.travaglini@arm.comEXPECT_NO_THROW({ 6613481Sgiacomo.travaglini@arm.com int n = 5; 6713481Sgiacomo.travaglini@arm.com Bar(&n); 6813481Sgiacomo.travaglini@arm.com}); 6913481Sgiacomo.travaglini@arm.com``` 7013481Sgiacomo.travaglini@arm.com 7113481Sgiacomo.travaglini@arm.com_Availability_: Linux, Windows, Mac; since version 1.1.0. 7213481Sgiacomo.travaglini@arm.com 7313481Sgiacomo.travaglini@arm.com## Predicate Assertions for Better Error Messages ## 7413481Sgiacomo.travaglini@arm.com 7513481Sgiacomo.travaglini@arm.comEven though Google Test has a rich set of assertions, they can never be 7613481Sgiacomo.travaglini@arm.comcomplete, as it's impossible (nor a good idea) to anticipate all the scenarios 7713481Sgiacomo.travaglini@arm.coma user might run into. Therefore, sometimes a user has to use `EXPECT_TRUE()` 7813481Sgiacomo.travaglini@arm.comto check a complex expression, for lack of a better macro. This has the problem 7913481Sgiacomo.travaglini@arm.comof not showing you the values of the parts of the expression, making it hard to 8013481Sgiacomo.travaglini@arm.comunderstand what went wrong. As a workaround, some users choose to construct the 8113481Sgiacomo.travaglini@arm.comfailure message by themselves, streaming it into `EXPECT_TRUE()`. However, this 8213481Sgiacomo.travaglini@arm.comis awkward especially when the expression has side-effects or is expensive to 8313481Sgiacomo.travaglini@arm.comevaluate. 8413481Sgiacomo.travaglini@arm.com 8513481Sgiacomo.travaglini@arm.comGoogle Test gives you three different options to solve this problem: 8613481Sgiacomo.travaglini@arm.com 8713481Sgiacomo.travaglini@arm.com### Using an Existing Boolean Function ### 8813481Sgiacomo.travaglini@arm.com 8913481Sgiacomo.travaglini@arm.comIf you already have a function or a functor that returns `bool` (or a type 9013481Sgiacomo.travaglini@arm.comthat can be implicitly converted to `bool`), you can use it in a _predicate 9113481Sgiacomo.travaglini@arm.comassertion_ to get the function arguments printed for free: 9213481Sgiacomo.travaglini@arm.com 9313481Sgiacomo.travaglini@arm.com| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | 9413481Sgiacomo.travaglini@arm.com|:--------------------|:-----------------------|:-------------| 9513481Sgiacomo.travaglini@arm.com| `ASSERT_PRED1(`_pred1, val1_`);` | `EXPECT_PRED1(`_pred1, val1_`);` | _pred1(val1)_ returns true | 9613481Sgiacomo.travaglini@arm.com| `ASSERT_PRED2(`_pred2, val1, val2_`);` | `EXPECT_PRED2(`_pred2, val1, val2_`);` | _pred2(val1, val2)_ returns true | 9713481Sgiacomo.travaglini@arm.com| ... | ... | ... | 9813481Sgiacomo.travaglini@arm.com 9913481Sgiacomo.travaglini@arm.comIn the above, _predn_ is an _n_-ary predicate function or functor, where 10013481Sgiacomo.travaglini@arm.com_val1_, _val2_, ..., and _valn_ are its arguments. The assertion succeeds 10113481Sgiacomo.travaglini@arm.comif the predicate returns `true` when applied to the given arguments, and fails 10213481Sgiacomo.travaglini@arm.comotherwise. When the assertion fails, it prints the value of each argument. In 10313481Sgiacomo.travaglini@arm.comeither case, the arguments are evaluated exactly once. 10413481Sgiacomo.travaglini@arm.com 10513481Sgiacomo.travaglini@arm.comHere's an example. Given 10613481Sgiacomo.travaglini@arm.com 10713481Sgiacomo.travaglini@arm.com``` 10813481Sgiacomo.travaglini@arm.com// Returns true iff m and n have no common divisors except 1. 10913481Sgiacomo.travaglini@arm.combool MutuallyPrime(int m, int n) { ... } 11013481Sgiacomo.travaglini@arm.comconst int a = 3; 11113481Sgiacomo.travaglini@arm.comconst int b = 4; 11213481Sgiacomo.travaglini@arm.comconst int c = 10; 11313481Sgiacomo.travaglini@arm.com``` 11413481Sgiacomo.travaglini@arm.com 11513481Sgiacomo.travaglini@arm.comthe assertion `EXPECT_PRED2(MutuallyPrime, a, b);` will succeed, while the 11613481Sgiacomo.travaglini@arm.comassertion `EXPECT_PRED2(MutuallyPrime, b, c);` will fail with the message 11713481Sgiacomo.travaglini@arm.com 11813481Sgiacomo.travaglini@arm.com<pre> 11913481Sgiacomo.travaglini@arm.com!MutuallyPrime(b, c) is false, where<br> 12013481Sgiacomo.travaglini@arm.comb is 4<br> 12113481Sgiacomo.travaglini@arm.comc is 10<br> 12213481Sgiacomo.travaglini@arm.com</pre> 12313481Sgiacomo.travaglini@arm.com 12413481Sgiacomo.travaglini@arm.com**Notes:** 12513481Sgiacomo.travaglini@arm.com 12613481Sgiacomo.travaglini@arm.com 1. If you see a compiler error "no matching function to call" when using `ASSERT_PRED*` or `EXPECT_PRED*`, please see [this](V1_7_FAQ.md#the-compiler-complains-about-undefined-references-to-some-static-const-member-variables-but-i-did-define-them-in-the-class-body-whats-wrong) for how to resolve it. 12713481Sgiacomo.travaglini@arm.com 1. Currently we only provide predicate assertions of arity <= 5. If you need a higher-arity assertion, let us know. 12813481Sgiacomo.travaglini@arm.com 12913481Sgiacomo.travaglini@arm.com_Availability_: Linux, Windows, Mac 13013481Sgiacomo.travaglini@arm.com 13113481Sgiacomo.travaglini@arm.com### Using a Function That Returns an AssertionResult ### 13213481Sgiacomo.travaglini@arm.com 13313481Sgiacomo.travaglini@arm.comWhile `EXPECT_PRED*()` and friends are handy for a quick job, the 13413481Sgiacomo.travaglini@arm.comsyntax is not satisfactory: you have to use different macros for 13513481Sgiacomo.travaglini@arm.comdifferent arities, and it feels more like Lisp than C++. The 13613481Sgiacomo.travaglini@arm.com`::testing::AssertionResult` class solves this problem. 13713481Sgiacomo.travaglini@arm.com 13813481Sgiacomo.travaglini@arm.comAn `AssertionResult` object represents the result of an assertion 13913481Sgiacomo.travaglini@arm.com(whether it's a success or a failure, and an associated message). You 14013481Sgiacomo.travaglini@arm.comcan create an `AssertionResult` using one of these factory 14113481Sgiacomo.travaglini@arm.comfunctions: 14213481Sgiacomo.travaglini@arm.com 14313481Sgiacomo.travaglini@arm.com``` 14413481Sgiacomo.travaglini@arm.comnamespace testing { 14513481Sgiacomo.travaglini@arm.com 14613481Sgiacomo.travaglini@arm.com// Returns an AssertionResult object to indicate that an assertion has 14713481Sgiacomo.travaglini@arm.com// succeeded. 14813481Sgiacomo.travaglini@arm.comAssertionResult AssertionSuccess(); 14913481Sgiacomo.travaglini@arm.com 15013481Sgiacomo.travaglini@arm.com// Returns an AssertionResult object to indicate that an assertion has 15113481Sgiacomo.travaglini@arm.com// failed. 15213481Sgiacomo.travaglini@arm.comAssertionResult AssertionFailure(); 15313481Sgiacomo.travaglini@arm.com 15413481Sgiacomo.travaglini@arm.com} 15513481Sgiacomo.travaglini@arm.com``` 15613481Sgiacomo.travaglini@arm.com 15713481Sgiacomo.travaglini@arm.comYou can then use the `<<` operator to stream messages to the 15813481Sgiacomo.travaglini@arm.com`AssertionResult` object. 15913481Sgiacomo.travaglini@arm.com 16013481Sgiacomo.travaglini@arm.comTo provide more readable messages in Boolean assertions 16113481Sgiacomo.travaglini@arm.com(e.g. `EXPECT_TRUE()`), write a predicate function that returns 16213481Sgiacomo.travaglini@arm.com`AssertionResult` instead of `bool`. For example, if you define 16313481Sgiacomo.travaglini@arm.com`IsEven()` as: 16413481Sgiacomo.travaglini@arm.com 16513481Sgiacomo.travaglini@arm.com``` 16613481Sgiacomo.travaglini@arm.com::testing::AssertionResult IsEven(int n) { 16713481Sgiacomo.travaglini@arm.com if ((n % 2) == 0) 16813481Sgiacomo.travaglini@arm.com return ::testing::AssertionSuccess(); 16913481Sgiacomo.travaglini@arm.com else 17013481Sgiacomo.travaglini@arm.com return ::testing::AssertionFailure() << n << " is odd"; 17113481Sgiacomo.travaglini@arm.com} 17213481Sgiacomo.travaglini@arm.com``` 17313481Sgiacomo.travaglini@arm.com 17413481Sgiacomo.travaglini@arm.cominstead of: 17513481Sgiacomo.travaglini@arm.com 17613481Sgiacomo.travaglini@arm.com``` 17713481Sgiacomo.travaglini@arm.combool IsEven(int n) { 17813481Sgiacomo.travaglini@arm.com return (n % 2) == 0; 17913481Sgiacomo.travaglini@arm.com} 18013481Sgiacomo.travaglini@arm.com``` 18113481Sgiacomo.travaglini@arm.com 18213481Sgiacomo.travaglini@arm.comthe failed assertion `EXPECT_TRUE(IsEven(Fib(4)))` will print: 18313481Sgiacomo.travaglini@arm.com 18413481Sgiacomo.travaglini@arm.com<pre> 18513481Sgiacomo.travaglini@arm.comValue of: IsEven(Fib(4))<br> 18613481Sgiacomo.travaglini@arm.comActual: false (*3 is odd*)<br> 18713481Sgiacomo.travaglini@arm.comExpected: true<br> 18813481Sgiacomo.travaglini@arm.com</pre> 18913481Sgiacomo.travaglini@arm.com 19013481Sgiacomo.travaglini@arm.cominstead of a more opaque 19113481Sgiacomo.travaglini@arm.com 19213481Sgiacomo.travaglini@arm.com<pre> 19313481Sgiacomo.travaglini@arm.comValue of: IsEven(Fib(4))<br> 19413481Sgiacomo.travaglini@arm.comActual: false<br> 19513481Sgiacomo.travaglini@arm.comExpected: true<br> 19613481Sgiacomo.travaglini@arm.com</pre> 19713481Sgiacomo.travaglini@arm.com 19813481Sgiacomo.travaglini@arm.comIf you want informative messages in `EXPECT_FALSE` and `ASSERT_FALSE` 19913481Sgiacomo.travaglini@arm.comas well, and are fine with making the predicate slower in the success 20013481Sgiacomo.travaglini@arm.comcase, you can supply a success message: 20113481Sgiacomo.travaglini@arm.com 20213481Sgiacomo.travaglini@arm.com``` 20313481Sgiacomo.travaglini@arm.com::testing::AssertionResult IsEven(int n) { 20413481Sgiacomo.travaglini@arm.com if ((n % 2) == 0) 20513481Sgiacomo.travaglini@arm.com return ::testing::AssertionSuccess() << n << " is even"; 20613481Sgiacomo.travaglini@arm.com else 20713481Sgiacomo.travaglini@arm.com return ::testing::AssertionFailure() << n << " is odd"; 20813481Sgiacomo.travaglini@arm.com} 20913481Sgiacomo.travaglini@arm.com``` 21013481Sgiacomo.travaglini@arm.com 21113481Sgiacomo.travaglini@arm.comThen the statement `EXPECT_FALSE(IsEven(Fib(6)))` will print 21213481Sgiacomo.travaglini@arm.com 21313481Sgiacomo.travaglini@arm.com<pre> 21413481Sgiacomo.travaglini@arm.comValue of: IsEven(Fib(6))<br> 21513481Sgiacomo.travaglini@arm.comActual: true (8 is even)<br> 21613481Sgiacomo.travaglini@arm.comExpected: false<br> 21713481Sgiacomo.travaglini@arm.com</pre> 21813481Sgiacomo.travaglini@arm.com 21913481Sgiacomo.travaglini@arm.com_Availability_: Linux, Windows, Mac; since version 1.4.1. 22013481Sgiacomo.travaglini@arm.com 22113481Sgiacomo.travaglini@arm.com### Using a Predicate-Formatter ### 22213481Sgiacomo.travaglini@arm.com 22313481Sgiacomo.travaglini@arm.comIf you find the default message generated by `(ASSERT|EXPECT)_PRED*` and 22413481Sgiacomo.travaglini@arm.com`(ASSERT|EXPECT)_(TRUE|FALSE)` unsatisfactory, or some arguments to your 22513481Sgiacomo.travaglini@arm.compredicate do not support streaming to `ostream`, you can instead use the 22613481Sgiacomo.travaglini@arm.comfollowing _predicate-formatter assertions_ to _fully_ customize how the 22713481Sgiacomo.travaglini@arm.commessage is formatted: 22813481Sgiacomo.travaglini@arm.com 22913481Sgiacomo.travaglini@arm.com| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | 23013481Sgiacomo.travaglini@arm.com|:--------------------|:-----------------------|:-------------| 23113481Sgiacomo.travaglini@arm.com| `ASSERT_PRED_FORMAT1(`_pred\_format1, val1_`);` | `EXPECT_PRED_FORMAT1(`_pred\_format1, val1_`); | _pred\_format1(val1)_ is successful | 23213481Sgiacomo.travaglini@arm.com| `ASSERT_PRED_FORMAT2(`_pred\_format2, val1, val2_`);` | `EXPECT_PRED_FORMAT2(`_pred\_format2, val1, val2_`);` | _pred\_format2(val1, val2)_ is successful | 23313481Sgiacomo.travaglini@arm.com| `...` | `...` | `...` | 23413481Sgiacomo.travaglini@arm.com 23513481Sgiacomo.travaglini@arm.comThe difference between this and the previous two groups of macros is that instead of 23613481Sgiacomo.travaglini@arm.coma predicate, `(ASSERT|EXPECT)_PRED_FORMAT*` take a _predicate-formatter_ 23713481Sgiacomo.travaglini@arm.com(_pred\_formatn_), which is a function or functor with the signature: 23813481Sgiacomo.travaglini@arm.com 23913481Sgiacomo.travaglini@arm.com`::testing::AssertionResult PredicateFormattern(const char* `_expr1_`, const char* `_expr2_`, ... const char* `_exprn_`, T1 `_val1_`, T2 `_val2_`, ... Tn `_valn_`);` 24013481Sgiacomo.travaglini@arm.com 24113481Sgiacomo.travaglini@arm.comwhere _val1_, _val2_, ..., and _valn_ are the values of the predicate 24213481Sgiacomo.travaglini@arm.comarguments, and _expr1_, _expr2_, ..., and _exprn_ are the corresponding 24313481Sgiacomo.travaglini@arm.comexpressions as they appear in the source code. The types `T1`, `T2`, ..., and 24413481Sgiacomo.travaglini@arm.com`Tn` can be either value types or reference types. For example, if an 24513481Sgiacomo.travaglini@arm.comargument has type `Foo`, you can declare it as either `Foo` or `const Foo&`, 24613481Sgiacomo.travaglini@arm.comwhichever is appropriate. 24713481Sgiacomo.travaglini@arm.com 24813481Sgiacomo.travaglini@arm.comA predicate-formatter returns a `::testing::AssertionResult` object to indicate 24913481Sgiacomo.travaglini@arm.comwhether the assertion has succeeded or not. The only way to create such an 25013481Sgiacomo.travaglini@arm.comobject is to call one of these factory functions: 25113481Sgiacomo.travaglini@arm.com 25213481Sgiacomo.travaglini@arm.comAs an example, let's improve the failure message in the previous example, which uses `EXPECT_PRED2()`: 25313481Sgiacomo.travaglini@arm.com 25413481Sgiacomo.travaglini@arm.com``` 25513481Sgiacomo.travaglini@arm.com// Returns the smallest prime common divisor of m and n, 25613481Sgiacomo.travaglini@arm.com// or 1 when m and n are mutually prime. 25713481Sgiacomo.travaglini@arm.comint SmallestPrimeCommonDivisor(int m, int n) { ... } 25813481Sgiacomo.travaglini@arm.com 25913481Sgiacomo.travaglini@arm.com// A predicate-formatter for asserting that two integers are mutually prime. 26013481Sgiacomo.travaglini@arm.com::testing::AssertionResult AssertMutuallyPrime(const char* m_expr, 26113481Sgiacomo.travaglini@arm.com const char* n_expr, 26213481Sgiacomo.travaglini@arm.com int m, 26313481Sgiacomo.travaglini@arm.com int n) { 26413481Sgiacomo.travaglini@arm.com if (MutuallyPrime(m, n)) 26513481Sgiacomo.travaglini@arm.com return ::testing::AssertionSuccess(); 26613481Sgiacomo.travaglini@arm.com 26713481Sgiacomo.travaglini@arm.com return ::testing::AssertionFailure() 26813481Sgiacomo.travaglini@arm.com << m_expr << " and " << n_expr << " (" << m << " and " << n 26913481Sgiacomo.travaglini@arm.com << ") are not mutually prime, " << "as they have a common divisor " 27013481Sgiacomo.travaglini@arm.com << SmallestPrimeCommonDivisor(m, n); 27113481Sgiacomo.travaglini@arm.com} 27213481Sgiacomo.travaglini@arm.com``` 27313481Sgiacomo.travaglini@arm.com 27413481Sgiacomo.travaglini@arm.comWith this predicate-formatter, we can use 27513481Sgiacomo.travaglini@arm.com 27613481Sgiacomo.travaglini@arm.com``` 27713481Sgiacomo.travaglini@arm.comEXPECT_PRED_FORMAT2(AssertMutuallyPrime, b, c); 27813481Sgiacomo.travaglini@arm.com``` 27913481Sgiacomo.travaglini@arm.com 28013481Sgiacomo.travaglini@arm.comto generate the message 28113481Sgiacomo.travaglini@arm.com 28213481Sgiacomo.travaglini@arm.com<pre> 28313481Sgiacomo.travaglini@arm.comb and c (4 and 10) are not mutually prime, as they have a common divisor 2.<br> 28413481Sgiacomo.travaglini@arm.com</pre> 28513481Sgiacomo.travaglini@arm.com 28613481Sgiacomo.travaglini@arm.comAs you may have realized, many of the assertions we introduced earlier are 28713481Sgiacomo.travaglini@arm.comspecial cases of `(EXPECT|ASSERT)_PRED_FORMAT*`. In fact, most of them are 28813481Sgiacomo.travaglini@arm.comindeed defined using `(EXPECT|ASSERT)_PRED_FORMAT*`. 28913481Sgiacomo.travaglini@arm.com 29013481Sgiacomo.travaglini@arm.com_Availability_: Linux, Windows, Mac. 29113481Sgiacomo.travaglini@arm.com 29213481Sgiacomo.travaglini@arm.com 29313481Sgiacomo.travaglini@arm.com## Floating-Point Comparison ## 29413481Sgiacomo.travaglini@arm.com 29513481Sgiacomo.travaglini@arm.comComparing floating-point numbers is tricky. Due to round-off errors, it is 29613481Sgiacomo.travaglini@arm.comvery unlikely that two floating-points will match exactly. Therefore, 29713481Sgiacomo.travaglini@arm.com`ASSERT_EQ` 's naive comparison usually doesn't work. And since floating-points 29813481Sgiacomo.travaglini@arm.comcan have a wide value range, no single fixed error bound works. It's better to 29913481Sgiacomo.travaglini@arm.comcompare by a fixed relative error bound, except for values close to 0 due to 30013481Sgiacomo.travaglini@arm.comthe loss of precision there. 30113481Sgiacomo.travaglini@arm.com 30213481Sgiacomo.travaglini@arm.comIn general, for floating-point comparison to make sense, the user needs to 30313481Sgiacomo.travaglini@arm.comcarefully choose the error bound. If they don't want or care to, comparing in 30413481Sgiacomo.travaglini@arm.comterms of Units in the Last Place (ULPs) is a good default, and Google Test 30513481Sgiacomo.travaglini@arm.comprovides assertions to do this. Full details about ULPs are quite long; if you 30613481Sgiacomo.travaglini@arm.comwant to learn more, see 30713481Sgiacomo.travaglini@arm.com[this article on float comparison](http://www.cygnus-software.com/papers/comparingfloats/comparingfloats.htm). 30813481Sgiacomo.travaglini@arm.com 30913481Sgiacomo.travaglini@arm.com### Floating-Point Macros ### 31013481Sgiacomo.travaglini@arm.com 31113481Sgiacomo.travaglini@arm.com| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | 31213481Sgiacomo.travaglini@arm.com|:--------------------|:-----------------------|:-------------| 31313481Sgiacomo.travaglini@arm.com| `ASSERT_FLOAT_EQ(`_expected, actual_`);` | `EXPECT_FLOAT_EQ(`_expected, actual_`);` | the two `float` values are almost equal | 31413481Sgiacomo.travaglini@arm.com| `ASSERT_DOUBLE_EQ(`_expected, actual_`);` | `EXPECT_DOUBLE_EQ(`_expected, actual_`);` | the two `double` values are almost equal | 31513481Sgiacomo.travaglini@arm.com 31613481Sgiacomo.travaglini@arm.comBy "almost equal", we mean the two values are within 4 ULP's from each 31713481Sgiacomo.travaglini@arm.comother. 31813481Sgiacomo.travaglini@arm.com 31913481Sgiacomo.travaglini@arm.comThe following assertions allow you to choose the acceptable error bound: 32013481Sgiacomo.travaglini@arm.com 32113481Sgiacomo.travaglini@arm.com| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | 32213481Sgiacomo.travaglini@arm.com|:--------------------|:-----------------------|:-------------| 32313481Sgiacomo.travaglini@arm.com| `ASSERT_NEAR(`_val1, val2, abs\_error_`);` | `EXPECT_NEAR`_(val1, val2, abs\_error_`);` | the difference between _val1_ and _val2_ doesn't exceed the given absolute error | 32413481Sgiacomo.travaglini@arm.com 32513481Sgiacomo.travaglini@arm.com_Availability_: Linux, Windows, Mac. 32613481Sgiacomo.travaglini@arm.com 32713481Sgiacomo.travaglini@arm.com### Floating-Point Predicate-Format Functions ### 32813481Sgiacomo.travaglini@arm.com 32913481Sgiacomo.travaglini@arm.comSome floating-point operations are useful, but not that often used. In order 33013481Sgiacomo.travaglini@arm.comto avoid an explosion of new macros, we provide them as predicate-format 33113481Sgiacomo.travaglini@arm.comfunctions that can be used in predicate assertion macros (e.g. 33213481Sgiacomo.travaglini@arm.com`EXPECT_PRED_FORMAT2`, etc). 33313481Sgiacomo.travaglini@arm.com 33413481Sgiacomo.travaglini@arm.com``` 33513481Sgiacomo.travaglini@arm.comEXPECT_PRED_FORMAT2(::testing::FloatLE, val1, val2); 33613481Sgiacomo.travaglini@arm.comEXPECT_PRED_FORMAT2(::testing::DoubleLE, val1, val2); 33713481Sgiacomo.travaglini@arm.com``` 33813481Sgiacomo.travaglini@arm.com 33913481Sgiacomo.travaglini@arm.comVerifies that _val1_ is less than, or almost equal to, _val2_. You can 34013481Sgiacomo.travaglini@arm.comreplace `EXPECT_PRED_FORMAT2` in the above table with `ASSERT_PRED_FORMAT2`. 34113481Sgiacomo.travaglini@arm.com 34213481Sgiacomo.travaglini@arm.com_Availability_: Linux, Windows, Mac. 34313481Sgiacomo.travaglini@arm.com 34413481Sgiacomo.travaglini@arm.com## Windows HRESULT assertions ## 34513481Sgiacomo.travaglini@arm.com 34613481Sgiacomo.travaglini@arm.comThese assertions test for `HRESULT` success or failure. 34713481Sgiacomo.travaglini@arm.com 34813481Sgiacomo.travaglini@arm.com| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | 34913481Sgiacomo.travaglini@arm.com|:--------------------|:-----------------------|:-------------| 35013481Sgiacomo.travaglini@arm.com| `ASSERT_HRESULT_SUCCEEDED(`_expression_`);` | `EXPECT_HRESULT_SUCCEEDED(`_expression_`);` | _expression_ is a success `HRESULT` | 35113481Sgiacomo.travaglini@arm.com| `ASSERT_HRESULT_FAILED(`_expression_`);` | `EXPECT_HRESULT_FAILED(`_expression_`);` | _expression_ is a failure `HRESULT` | 35213481Sgiacomo.travaglini@arm.com 35313481Sgiacomo.travaglini@arm.comThe generated output contains the human-readable error message 35413481Sgiacomo.travaglini@arm.comassociated with the `HRESULT` code returned by _expression_. 35513481Sgiacomo.travaglini@arm.com 35613481Sgiacomo.travaglini@arm.comYou might use them like this: 35713481Sgiacomo.travaglini@arm.com 35813481Sgiacomo.travaglini@arm.com``` 35913481Sgiacomo.travaglini@arm.comCComPtr shell; 36013481Sgiacomo.travaglini@arm.comASSERT_HRESULT_SUCCEEDED(shell.CoCreateInstance(L"Shell.Application")); 36113481Sgiacomo.travaglini@arm.comCComVariant empty; 36213481Sgiacomo.travaglini@arm.comASSERT_HRESULT_SUCCEEDED(shell->ShellExecute(CComBSTR(url), empty, empty, empty, empty)); 36313481Sgiacomo.travaglini@arm.com``` 36413481Sgiacomo.travaglini@arm.com 36513481Sgiacomo.travaglini@arm.com_Availability_: Windows. 36613481Sgiacomo.travaglini@arm.com 36713481Sgiacomo.travaglini@arm.com## Type Assertions ## 36813481Sgiacomo.travaglini@arm.com 36913481Sgiacomo.travaglini@arm.comYou can call the function 37013481Sgiacomo.travaglini@arm.com``` 37113481Sgiacomo.travaglini@arm.com::testing::StaticAssertTypeEq<T1, T2>(); 37213481Sgiacomo.travaglini@arm.com``` 37313481Sgiacomo.travaglini@arm.comto assert that types `T1` and `T2` are the same. The function does 37413481Sgiacomo.travaglini@arm.comnothing if the assertion is satisfied. If the types are different, 37513481Sgiacomo.travaglini@arm.comthe function call will fail to compile, and the compiler error message 37613481Sgiacomo.travaglini@arm.comwill likely (depending on the compiler) show you the actual values of 37713481Sgiacomo.travaglini@arm.com`T1` and `T2`. This is mainly useful inside template code. 37813481Sgiacomo.travaglini@arm.com 37913481Sgiacomo.travaglini@arm.com_Caveat:_ When used inside a member function of a class template or a 38013481Sgiacomo.travaglini@arm.comfunction template, `StaticAssertTypeEq<T1, T2>()` is effective _only if_ 38113481Sgiacomo.travaglini@arm.comthe function is instantiated. For example, given: 38213481Sgiacomo.travaglini@arm.com``` 38313481Sgiacomo.travaglini@arm.comtemplate <typename T> class Foo { 38413481Sgiacomo.travaglini@arm.com public: 38513481Sgiacomo.travaglini@arm.com void Bar() { ::testing::StaticAssertTypeEq<int, T>(); } 38613481Sgiacomo.travaglini@arm.com}; 38713481Sgiacomo.travaglini@arm.com``` 38813481Sgiacomo.travaglini@arm.comthe code: 38913481Sgiacomo.travaglini@arm.com``` 39013481Sgiacomo.travaglini@arm.comvoid Test1() { Foo<bool> foo; } 39113481Sgiacomo.travaglini@arm.com``` 39213481Sgiacomo.travaglini@arm.comwill _not_ generate a compiler error, as `Foo<bool>::Bar()` is never 39313481Sgiacomo.travaglini@arm.comactually instantiated. Instead, you need: 39413481Sgiacomo.travaglini@arm.com``` 39513481Sgiacomo.travaglini@arm.comvoid Test2() { Foo<bool> foo; foo.Bar(); } 39613481Sgiacomo.travaglini@arm.com``` 39713481Sgiacomo.travaglini@arm.comto cause a compiler error. 39813481Sgiacomo.travaglini@arm.com 39913481Sgiacomo.travaglini@arm.com_Availability:_ Linux, Windows, Mac; since version 1.3.0. 40013481Sgiacomo.travaglini@arm.com 40113481Sgiacomo.travaglini@arm.com## Assertion Placement ## 40213481Sgiacomo.travaglini@arm.com 40313481Sgiacomo.travaglini@arm.comYou can use assertions in any C++ function. In particular, it doesn't 40413481Sgiacomo.travaglini@arm.comhave to be a method of the test fixture class. The one constraint is 40513481Sgiacomo.travaglini@arm.comthat assertions that generate a fatal failure (`FAIL*` and `ASSERT_*`) 40613481Sgiacomo.travaglini@arm.comcan only be used in void-returning functions. This is a consequence of 40713481Sgiacomo.travaglini@arm.comGoogle Test not using exceptions. By placing it in a non-void function 40813481Sgiacomo.travaglini@arm.comyou'll get a confusing compile error like 40913481Sgiacomo.travaglini@arm.com`"error: void value not ignored as it ought to be"`. 41013481Sgiacomo.travaglini@arm.com 41113481Sgiacomo.travaglini@arm.comIf you need to use assertions in a function that returns non-void, one option 41213481Sgiacomo.travaglini@arm.comis to make the function return the value in an out parameter instead. For 41313481Sgiacomo.travaglini@arm.comexample, you can rewrite `T2 Foo(T1 x)` to `void Foo(T1 x, T2* result)`. You 41413481Sgiacomo.travaglini@arm.comneed to make sure that `*result` contains some sensible value even when the 41513481Sgiacomo.travaglini@arm.comfunction returns prematurely. As the function now returns `void`, you can use 41613481Sgiacomo.travaglini@arm.comany assertion inside of it. 41713481Sgiacomo.travaglini@arm.com 41813481Sgiacomo.travaglini@arm.comIf changing the function's type is not an option, you should just use 41913481Sgiacomo.travaglini@arm.comassertions that generate non-fatal failures, such as `ADD_FAILURE*` and 42013481Sgiacomo.travaglini@arm.com`EXPECT_*`. 42113481Sgiacomo.travaglini@arm.com 42213481Sgiacomo.travaglini@arm.com_Note_: Constructors and destructors are not considered void-returning 42313481Sgiacomo.travaglini@arm.comfunctions, according to the C++ language specification, and so you may not use 42413481Sgiacomo.travaglini@arm.comfatal assertions in them. You'll get a compilation error if you try. A simple 42513481Sgiacomo.travaglini@arm.comworkaround is to transfer the entire body of the constructor or destructor to a 42613481Sgiacomo.travaglini@arm.comprivate void-returning method. However, you should be aware that a fatal 42713481Sgiacomo.travaglini@arm.comassertion failure in a constructor does not terminate the current test, as your 42813481Sgiacomo.travaglini@arm.comintuition might suggest; it merely returns from the constructor early, possibly 42913481Sgiacomo.travaglini@arm.comleaving your object in a partially-constructed state. Likewise, a fatal 43013481Sgiacomo.travaglini@arm.comassertion failure in a destructor may leave your object in a 43113481Sgiacomo.travaglini@arm.compartially-destructed state. Use assertions carefully in these situations! 43213481Sgiacomo.travaglini@arm.com 43313481Sgiacomo.travaglini@arm.com# Teaching Google Test How to Print Your Values # 43413481Sgiacomo.travaglini@arm.com 43513481Sgiacomo.travaglini@arm.comWhen a test assertion such as `EXPECT_EQ` fails, Google Test prints the 43613481Sgiacomo.travaglini@arm.comargument values to help you debug. It does this using a 43713481Sgiacomo.travaglini@arm.comuser-extensible value printer. 43813481Sgiacomo.travaglini@arm.com 43913481Sgiacomo.travaglini@arm.comThis printer knows how to print built-in C++ types, native arrays, STL 44013481Sgiacomo.travaglini@arm.comcontainers, and any type that supports the `<<` operator. For other 44113481Sgiacomo.travaglini@arm.comtypes, it prints the raw bytes in the value and hopes that you the 44213481Sgiacomo.travaglini@arm.comuser can figure it out. 44313481Sgiacomo.travaglini@arm.com 44413481Sgiacomo.travaglini@arm.comAs mentioned earlier, the printer is _extensible_. That means 44513481Sgiacomo.travaglini@arm.comyou can teach it to do a better job at printing your particular type 44613481Sgiacomo.travaglini@arm.comthan to dump the bytes. To do that, define `<<` for your type: 44713481Sgiacomo.travaglini@arm.com 44813481Sgiacomo.travaglini@arm.com``` 44913481Sgiacomo.travaglini@arm.com#include <iostream> 45013481Sgiacomo.travaglini@arm.com 45113481Sgiacomo.travaglini@arm.comnamespace foo { 45213481Sgiacomo.travaglini@arm.com 45313481Sgiacomo.travaglini@arm.comclass Bar { ... }; // We want Google Test to be able to print instances of this. 45413481Sgiacomo.travaglini@arm.com 45513481Sgiacomo.travaglini@arm.com// It's important that the << operator is defined in the SAME 45613481Sgiacomo.travaglini@arm.com// namespace that defines Bar. C++'s look-up rules rely on that. 45713481Sgiacomo.travaglini@arm.com::std::ostream& operator<<(::std::ostream& os, const Bar& bar) { 45813481Sgiacomo.travaglini@arm.com return os << bar.DebugString(); // whatever needed to print bar to os 45913481Sgiacomo.travaglini@arm.com} 46013481Sgiacomo.travaglini@arm.com 46113481Sgiacomo.travaglini@arm.com} // namespace foo 46213481Sgiacomo.travaglini@arm.com``` 46313481Sgiacomo.travaglini@arm.com 46413481Sgiacomo.travaglini@arm.comSometimes, this might not be an option: your team may consider it bad 46513481Sgiacomo.travaglini@arm.comstyle to have a `<<` operator for `Bar`, or `Bar` may already have a 46613481Sgiacomo.travaglini@arm.com`<<` operator that doesn't do what you want (and you cannot change 46713481Sgiacomo.travaglini@arm.comit). If so, you can instead define a `PrintTo()` function like this: 46813481Sgiacomo.travaglini@arm.com 46913481Sgiacomo.travaglini@arm.com``` 47013481Sgiacomo.travaglini@arm.com#include <iostream> 47113481Sgiacomo.travaglini@arm.com 47213481Sgiacomo.travaglini@arm.comnamespace foo { 47313481Sgiacomo.travaglini@arm.com 47413481Sgiacomo.travaglini@arm.comclass Bar { ... }; 47513481Sgiacomo.travaglini@arm.com 47613481Sgiacomo.travaglini@arm.com// It's important that PrintTo() is defined in the SAME 47713481Sgiacomo.travaglini@arm.com// namespace that defines Bar. C++'s look-up rules rely on that. 47813481Sgiacomo.travaglini@arm.comvoid PrintTo(const Bar& bar, ::std::ostream* os) { 47913481Sgiacomo.travaglini@arm.com *os << bar.DebugString(); // whatever needed to print bar to os 48013481Sgiacomo.travaglini@arm.com} 48113481Sgiacomo.travaglini@arm.com 48213481Sgiacomo.travaglini@arm.com} // namespace foo 48313481Sgiacomo.travaglini@arm.com``` 48413481Sgiacomo.travaglini@arm.com 48513481Sgiacomo.travaglini@arm.comIf you have defined both `<<` and `PrintTo()`, the latter will be used 48613481Sgiacomo.travaglini@arm.comwhen Google Test is concerned. This allows you to customize how the value 48713481Sgiacomo.travaglini@arm.comappears in Google Test's output without affecting code that relies on the 48813481Sgiacomo.travaglini@arm.combehavior of its `<<` operator. 48913481Sgiacomo.travaglini@arm.com 49013481Sgiacomo.travaglini@arm.comIf you want to print a value `x` using Google Test's value printer 49113481Sgiacomo.travaglini@arm.comyourself, just call `::testing::PrintToString(`_x_`)`, which 49213481Sgiacomo.travaglini@arm.comreturns an `std::string`: 49313481Sgiacomo.travaglini@arm.com 49413481Sgiacomo.travaglini@arm.com``` 49513481Sgiacomo.travaglini@arm.comvector<pair<Bar, int> > bar_ints = GetBarIntVector(); 49613481Sgiacomo.travaglini@arm.com 49713481Sgiacomo.travaglini@arm.comEXPECT_TRUE(IsCorrectBarIntVector(bar_ints)) 49813481Sgiacomo.travaglini@arm.com << "bar_ints = " << ::testing::PrintToString(bar_ints); 49913481Sgiacomo.travaglini@arm.com``` 50013481Sgiacomo.travaglini@arm.com 50113481Sgiacomo.travaglini@arm.com# Death Tests # 50213481Sgiacomo.travaglini@arm.com 50313481Sgiacomo.travaglini@arm.comIn many applications, there are assertions that can cause application failure 50413481Sgiacomo.travaglini@arm.comif a condition is not met. These sanity checks, which ensure that the program 50513481Sgiacomo.travaglini@arm.comis in a known good state, are there to fail at the earliest possible time after 50613481Sgiacomo.travaglini@arm.comsome program state is corrupted. If the assertion checks the wrong condition, 50713481Sgiacomo.travaglini@arm.comthen the program may proceed in an erroneous state, which could lead to memory 50813481Sgiacomo.travaglini@arm.comcorruption, security holes, or worse. Hence it is vitally important to test 50913481Sgiacomo.travaglini@arm.comthat such assertion statements work as expected. 51013481Sgiacomo.travaglini@arm.com 51113481Sgiacomo.travaglini@arm.comSince these precondition checks cause the processes to die, we call such tests 51213481Sgiacomo.travaglini@arm.com_death tests_. More generally, any test that checks that a program terminates 51313481Sgiacomo.travaglini@arm.com(except by throwing an exception) in an expected fashion is also a death test. 51413481Sgiacomo.travaglini@arm.com 51513481Sgiacomo.travaglini@arm.comNote that if a piece of code throws an exception, we don't consider it "death" 51613481Sgiacomo.travaglini@arm.comfor the purpose of death tests, as the caller of the code could catch the exception 51713481Sgiacomo.travaglini@arm.comand avoid the crash. If you want to verify exceptions thrown by your code, 51813481Sgiacomo.travaglini@arm.comsee [Exception Assertions](#exception-assertions). 51913481Sgiacomo.travaglini@arm.com 52013481Sgiacomo.travaglini@arm.comIf you want to test `EXPECT_*()/ASSERT_*()` failures in your test code, see [Catching Failures](#catching-failures). 52113481Sgiacomo.travaglini@arm.com 52213481Sgiacomo.travaglini@arm.com## How to Write a Death Test ## 52313481Sgiacomo.travaglini@arm.com 52413481Sgiacomo.travaglini@arm.comGoogle Test has the following macros to support death tests: 52513481Sgiacomo.travaglini@arm.com 52613481Sgiacomo.travaglini@arm.com| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | 52713481Sgiacomo.travaglini@arm.com|:--------------------|:-----------------------|:-------------| 52813481Sgiacomo.travaglini@arm.com| `ASSERT_DEATH(`_statement, regex_`); | `EXPECT_DEATH(`_statement, regex_`); | _statement_ crashes with the given error | 52913481Sgiacomo.travaglini@arm.com| `ASSERT_DEATH_IF_SUPPORTED(`_statement, regex_`); | `EXPECT_DEATH_IF_SUPPORTED(`_statement, regex_`); | if death tests are supported, verifies that _statement_ crashes with the given error; otherwise verifies nothing | 53013481Sgiacomo.travaglini@arm.com| `ASSERT_EXIT(`_statement, predicate, regex_`); | `EXPECT_EXIT(`_statement, predicate, regex_`); |_statement_ exits with the given error and its exit code matches _predicate_ | 53113481Sgiacomo.travaglini@arm.com 53213481Sgiacomo.travaglini@arm.comwhere _statement_ is a statement that is expected to cause the process to 53313481Sgiacomo.travaglini@arm.comdie, _predicate_ is a function or function object that evaluates an integer 53413481Sgiacomo.travaglini@arm.comexit status, and _regex_ is a regular expression that the stderr output of 53513481Sgiacomo.travaglini@arm.com_statement_ is expected to match. Note that _statement_ can be _any valid 53613481Sgiacomo.travaglini@arm.comstatement_ (including _compound statement_) and doesn't have to be an 53713481Sgiacomo.travaglini@arm.comexpression. 53813481Sgiacomo.travaglini@arm.com 53913481Sgiacomo.travaglini@arm.comAs usual, the `ASSERT` variants abort the current test function, while the 54013481Sgiacomo.travaglini@arm.com`EXPECT` variants do not. 54113481Sgiacomo.travaglini@arm.com 54213481Sgiacomo.travaglini@arm.com**Note:** We use the word "crash" here to mean that the process 54313481Sgiacomo.travaglini@arm.comterminates with a _non-zero_ exit status code. There are two 54413481Sgiacomo.travaglini@arm.compossibilities: either the process has called `exit()` or `_exit()` 54513481Sgiacomo.travaglini@arm.comwith a non-zero value, or it may be killed by a signal. 54613481Sgiacomo.travaglini@arm.com 54713481Sgiacomo.travaglini@arm.comThis means that if _statement_ terminates the process with a 0 exit 54813481Sgiacomo.travaglini@arm.comcode, it is _not_ considered a crash by `EXPECT_DEATH`. Use 54913481Sgiacomo.travaglini@arm.com`EXPECT_EXIT` instead if this is the case, or if you want to restrict 55013481Sgiacomo.travaglini@arm.comthe exit code more precisely. 55113481Sgiacomo.travaglini@arm.com 55213481Sgiacomo.travaglini@arm.comA predicate here must accept an `int` and return a `bool`. The death test 55313481Sgiacomo.travaglini@arm.comsucceeds only if the predicate returns `true`. Google Test defines a few 55413481Sgiacomo.travaglini@arm.compredicates that handle the most common cases: 55513481Sgiacomo.travaglini@arm.com 55613481Sgiacomo.travaglini@arm.com``` 55713481Sgiacomo.travaglini@arm.com::testing::ExitedWithCode(exit_code) 55813481Sgiacomo.travaglini@arm.com``` 55913481Sgiacomo.travaglini@arm.com 56013481Sgiacomo.travaglini@arm.comThis expression is `true` if the program exited normally with the given exit 56113481Sgiacomo.travaglini@arm.comcode. 56213481Sgiacomo.travaglini@arm.com 56313481Sgiacomo.travaglini@arm.com``` 56413481Sgiacomo.travaglini@arm.com::testing::KilledBySignal(signal_number) // Not available on Windows. 56513481Sgiacomo.travaglini@arm.com``` 56613481Sgiacomo.travaglini@arm.com 56713481Sgiacomo.travaglini@arm.comThis expression is `true` if the program was killed by the given signal. 56813481Sgiacomo.travaglini@arm.com 56913481Sgiacomo.travaglini@arm.comThe `*_DEATH` macros are convenient wrappers for `*_EXIT` that use a predicate 57013481Sgiacomo.travaglini@arm.comthat verifies the process' exit code is non-zero. 57113481Sgiacomo.travaglini@arm.com 57213481Sgiacomo.travaglini@arm.comNote that a death test only cares about three things: 57313481Sgiacomo.travaglini@arm.com 57413481Sgiacomo.travaglini@arm.com 1. does _statement_ abort or exit the process? 57513481Sgiacomo.travaglini@arm.com 1. (in the case of `ASSERT_EXIT` and `EXPECT_EXIT`) does the exit status satisfy _predicate_? Or (in the case of `ASSERT_DEATH` and `EXPECT_DEATH`) is the exit status non-zero? And 57613481Sgiacomo.travaglini@arm.com 1. does the stderr output match _regex_? 57713481Sgiacomo.travaglini@arm.com 57813481Sgiacomo.travaglini@arm.comIn particular, if _statement_ generates an `ASSERT_*` or `EXPECT_*` failure, it will **not** cause the death test to fail, as Google Test assertions don't abort the process. 57913481Sgiacomo.travaglini@arm.com 58013481Sgiacomo.travaglini@arm.comTo write a death test, simply use one of the above macros inside your test 58113481Sgiacomo.travaglini@arm.comfunction. For example, 58213481Sgiacomo.travaglini@arm.com 58313481Sgiacomo.travaglini@arm.com``` 58413481Sgiacomo.travaglini@arm.comTEST(MyDeathTest, Foo) { 58513481Sgiacomo.travaglini@arm.com // This death test uses a compound statement. 58613481Sgiacomo.travaglini@arm.com ASSERT_DEATH({ int n = 5; Foo(&n); }, "Error on line .* of Foo()"); 58713481Sgiacomo.travaglini@arm.com} 58813481Sgiacomo.travaglini@arm.comTEST(MyDeathTest, NormalExit) { 58913481Sgiacomo.travaglini@arm.com EXPECT_EXIT(NormalExit(), ::testing::ExitedWithCode(0), "Success"); 59013481Sgiacomo.travaglini@arm.com} 59113481Sgiacomo.travaglini@arm.comTEST(MyDeathTest, KillMyself) { 59213481Sgiacomo.travaglini@arm.com EXPECT_EXIT(KillMyself(), ::testing::KilledBySignal(SIGKILL), "Sending myself unblockable signal"); 59313481Sgiacomo.travaglini@arm.com} 59413481Sgiacomo.travaglini@arm.com``` 59513481Sgiacomo.travaglini@arm.com 59613481Sgiacomo.travaglini@arm.comverifies that: 59713481Sgiacomo.travaglini@arm.com 59813481Sgiacomo.travaglini@arm.com * calling `Foo(5)` causes the process to die with the given error message, 59913481Sgiacomo.travaglini@arm.com * calling `NormalExit()` causes the process to print `"Success"` to stderr and exit with exit code 0, and 60013481Sgiacomo.travaglini@arm.com * calling `KillMyself()` kills the process with signal `SIGKILL`. 60113481Sgiacomo.travaglini@arm.com 60213481Sgiacomo.travaglini@arm.comThe test function body may contain other assertions and statements as well, if 60313481Sgiacomo.travaglini@arm.comnecessary. 60413481Sgiacomo.travaglini@arm.com 60513481Sgiacomo.travaglini@arm.com_Important:_ We strongly recommend you to follow the convention of naming your 60613481Sgiacomo.travaglini@arm.comtest case (not test) `*DeathTest` when it contains a death test, as 60713481Sgiacomo.travaglini@arm.comdemonstrated in the above example. The `Death Tests And Threads` section below 60813481Sgiacomo.travaglini@arm.comexplains why. 60913481Sgiacomo.travaglini@arm.com 61013481Sgiacomo.travaglini@arm.comIf a test fixture class is shared by normal tests and death tests, you 61113481Sgiacomo.travaglini@arm.comcan use typedef to introduce an alias for the fixture class and avoid 61213481Sgiacomo.travaglini@arm.comduplicating its code: 61313481Sgiacomo.travaglini@arm.com``` 61413481Sgiacomo.travaglini@arm.comclass FooTest : public ::testing::Test { ... }; 61513481Sgiacomo.travaglini@arm.com 61613481Sgiacomo.travaglini@arm.comtypedef FooTest FooDeathTest; 61713481Sgiacomo.travaglini@arm.com 61813481Sgiacomo.travaglini@arm.comTEST_F(FooTest, DoesThis) { 61913481Sgiacomo.travaglini@arm.com // normal test 62013481Sgiacomo.travaglini@arm.com} 62113481Sgiacomo.travaglini@arm.com 62213481Sgiacomo.travaglini@arm.comTEST_F(FooDeathTest, DoesThat) { 62313481Sgiacomo.travaglini@arm.com // death test 62413481Sgiacomo.travaglini@arm.com} 62513481Sgiacomo.travaglini@arm.com``` 62613481Sgiacomo.travaglini@arm.com 62713481Sgiacomo.travaglini@arm.com_Availability:_ Linux, Windows (requires MSVC 8.0 or above), Cygwin, and Mac (the latter three are supported since v1.3.0). `(ASSERT|EXPECT)_DEATH_IF_SUPPORTED` are new in v1.4.0. 62813481Sgiacomo.travaglini@arm.com 62913481Sgiacomo.travaglini@arm.com## Regular Expression Syntax ## 63013481Sgiacomo.travaglini@arm.com 63113481Sgiacomo.travaglini@arm.comOn POSIX systems (e.g. Linux, Cygwin, and Mac), Google Test uses the 63213481Sgiacomo.travaglini@arm.com[POSIX extended regular expression](http://www.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap09.html#tag_09_04) 63313481Sgiacomo.travaglini@arm.comsyntax in death tests. To learn about this syntax, you may want to read this [Wikipedia entry](http://en.wikipedia.org/wiki/Regular_expression#POSIX_Extended_Regular_Expressions). 63413481Sgiacomo.travaglini@arm.com 63513481Sgiacomo.travaglini@arm.comOn Windows, Google Test uses its own simple regular expression 63613481Sgiacomo.travaglini@arm.comimplementation. It lacks many features you can find in POSIX extended 63713481Sgiacomo.travaglini@arm.comregular expressions. For example, we don't support union (`"x|y"`), 63813481Sgiacomo.travaglini@arm.comgrouping (`"(xy)"`), brackets (`"[xy]"`), and repetition count 63913481Sgiacomo.travaglini@arm.com(`"x{5,7}"`), among others. Below is what we do support (Letter `A` denotes a 64013481Sgiacomo.travaglini@arm.comliteral character, period (`.`), or a single `\\` escape sequence; `x` 64113481Sgiacomo.travaglini@arm.comand `y` denote regular expressions.): 64213481Sgiacomo.travaglini@arm.com 64313481Sgiacomo.travaglini@arm.com| `c` | matches any literal character `c` | 64413481Sgiacomo.travaglini@arm.com|:----|:----------------------------------| 64513481Sgiacomo.travaglini@arm.com| `\\d` | matches any decimal digit | 64613481Sgiacomo.travaglini@arm.com| `\\D` | matches any character that's not a decimal digit | 64713481Sgiacomo.travaglini@arm.com| `\\f` | matches `\f` | 64813481Sgiacomo.travaglini@arm.com| `\\n` | matches `\n` | 64913481Sgiacomo.travaglini@arm.com| `\\r` | matches `\r` | 65013481Sgiacomo.travaglini@arm.com| `\\s` | matches any ASCII whitespace, including `\n` | 65113481Sgiacomo.travaglini@arm.com| `\\S` | matches any character that's not a whitespace | 65213481Sgiacomo.travaglini@arm.com| `\\t` | matches `\t` | 65313481Sgiacomo.travaglini@arm.com| `\\v` | matches `\v` | 65413481Sgiacomo.travaglini@arm.com| `\\w` | matches any letter, `_`, or decimal digit | 65513481Sgiacomo.travaglini@arm.com| `\\W` | matches any character that `\\w` doesn't match | 65613481Sgiacomo.travaglini@arm.com| `\\c` | matches any literal character `c`, which must be a punctuation | 65713481Sgiacomo.travaglini@arm.com| `\\.` | matches the `.` character | 65813481Sgiacomo.travaglini@arm.com| `.` | matches any single character except `\n` | 65913481Sgiacomo.travaglini@arm.com| `A?` | matches 0 or 1 occurrences of `A` | 66013481Sgiacomo.travaglini@arm.com| `A*` | matches 0 or many occurrences of `A` | 66113481Sgiacomo.travaglini@arm.com| `A+` | matches 1 or many occurrences of `A` | 66213481Sgiacomo.travaglini@arm.com| `^` | matches the beginning of a string (not that of each line) | 66313481Sgiacomo.travaglini@arm.com| `$` | matches the end of a string (not that of each line) | 66413481Sgiacomo.travaglini@arm.com| `xy` | matches `x` followed by `y` | 66513481Sgiacomo.travaglini@arm.com 66613481Sgiacomo.travaglini@arm.comTo help you determine which capability is available on your system, 66713481Sgiacomo.travaglini@arm.comGoogle Test defines macro `GTEST_USES_POSIX_RE=1` when it uses POSIX 66813481Sgiacomo.travaglini@arm.comextended regular expressions, or `GTEST_USES_SIMPLE_RE=1` when it uses 66913481Sgiacomo.travaglini@arm.comthe simple version. If you want your death tests to work in both 67013481Sgiacomo.travaglini@arm.comcases, you can either `#if` on these macros or use the more limited 67113481Sgiacomo.travaglini@arm.comsyntax only. 67213481Sgiacomo.travaglini@arm.com 67313481Sgiacomo.travaglini@arm.com## How It Works ## 67413481Sgiacomo.travaglini@arm.com 67513481Sgiacomo.travaglini@arm.comUnder the hood, `ASSERT_EXIT()` spawns a new process and executes the 67613481Sgiacomo.travaglini@arm.comdeath test statement in that process. The details of of how precisely 67713481Sgiacomo.travaglini@arm.comthat happens depend on the platform and the variable 67813481Sgiacomo.travaglini@arm.com`::testing::GTEST_FLAG(death_test_style)` (which is initialized from the 67913481Sgiacomo.travaglini@arm.comcommand-line flag `--gtest_death_test_style`). 68013481Sgiacomo.travaglini@arm.com 68113481Sgiacomo.travaglini@arm.com * On POSIX systems, `fork()` (or `clone()` on Linux) is used to spawn the child, after which: 68213481Sgiacomo.travaglini@arm.com * If the variable's value is `"fast"`, the death test statement is immediately executed. 68313481Sgiacomo.travaglini@arm.com * If the variable's value is `"threadsafe"`, the child process re-executes the unit test binary just as it was originally invoked, but with some extra flags to cause just the single death test under consideration to be run. 68413481Sgiacomo.travaglini@arm.com * On Windows, the child is spawned using the `CreateProcess()` API, and re-executes the binary to cause just the single death test under consideration to be run - much like the `threadsafe` mode on POSIX. 68513481Sgiacomo.travaglini@arm.com 68613481Sgiacomo.travaglini@arm.comOther values for the variable are illegal and will cause the death test to 68713481Sgiacomo.travaglini@arm.comfail. Currently, the flag's default value is `"fast"`. However, we reserve the 68813481Sgiacomo.travaglini@arm.comright to change it in the future. Therefore, your tests should not depend on 68913481Sgiacomo.travaglini@arm.comthis. 69013481Sgiacomo.travaglini@arm.com 69113481Sgiacomo.travaglini@arm.comIn either case, the parent process waits for the child process to complete, and checks that 69213481Sgiacomo.travaglini@arm.com 69313481Sgiacomo.travaglini@arm.com 1. the child's exit status satisfies the predicate, and 69413481Sgiacomo.travaglini@arm.com 1. the child's stderr matches the regular expression. 69513481Sgiacomo.travaglini@arm.com 69613481Sgiacomo.travaglini@arm.comIf the death test statement runs to completion without dying, the child 69713481Sgiacomo.travaglini@arm.comprocess will nonetheless terminate, and the assertion fails. 69813481Sgiacomo.travaglini@arm.com 69913481Sgiacomo.travaglini@arm.com## Death Tests And Threads ## 70013481Sgiacomo.travaglini@arm.com 70113481Sgiacomo.travaglini@arm.comThe reason for the two death test styles has to do with thread safety. Due to 70213481Sgiacomo.travaglini@arm.comwell-known problems with forking in the presence of threads, death tests should 70313481Sgiacomo.travaglini@arm.combe run in a single-threaded context. Sometimes, however, it isn't feasible to 70413481Sgiacomo.travaglini@arm.comarrange that kind of environment. For example, statically-initialized modules 70513481Sgiacomo.travaglini@arm.commay start threads before main is ever reached. Once threads have been created, 70613481Sgiacomo.travaglini@arm.comit may be difficult or impossible to clean them up. 70713481Sgiacomo.travaglini@arm.com 70813481Sgiacomo.travaglini@arm.comGoogle Test has three features intended to raise awareness of threading issues. 70913481Sgiacomo.travaglini@arm.com 71013481Sgiacomo.travaglini@arm.com 1. A warning is emitted if multiple threads are running when a death test is encountered. 71113481Sgiacomo.travaglini@arm.com 1. Test cases with a name ending in "DeathTest" are run before all other tests. 71213481Sgiacomo.travaglini@arm.com 1. It uses `clone()` instead of `fork()` to spawn the child process on Linux (`clone()` is not available on Cygwin and Mac), as `fork()` is more likely to cause the child to hang when the parent process has multiple threads. 71313481Sgiacomo.travaglini@arm.com 71413481Sgiacomo.travaglini@arm.comIt's perfectly fine to create threads inside a death test statement; they are 71513481Sgiacomo.travaglini@arm.comexecuted in a separate process and cannot affect the parent. 71613481Sgiacomo.travaglini@arm.com 71713481Sgiacomo.travaglini@arm.com## Death Test Styles ## 71813481Sgiacomo.travaglini@arm.com 71913481Sgiacomo.travaglini@arm.comThe "threadsafe" death test style was introduced in order to help mitigate the 72013481Sgiacomo.travaglini@arm.comrisks of testing in a possibly multithreaded environment. It trades increased 72113481Sgiacomo.travaglini@arm.comtest execution time (potentially dramatically so) for improved thread safety. 72213481Sgiacomo.travaglini@arm.comWe suggest using the faster, default "fast" style unless your test has specific 72313481Sgiacomo.travaglini@arm.comproblems with it. 72413481Sgiacomo.travaglini@arm.com 72513481Sgiacomo.travaglini@arm.comYou can choose a particular style of death tests by setting the flag 72613481Sgiacomo.travaglini@arm.comprogrammatically: 72713481Sgiacomo.travaglini@arm.com 72813481Sgiacomo.travaglini@arm.com``` 72913481Sgiacomo.travaglini@arm.com::testing::FLAGS_gtest_death_test_style = "threadsafe"; 73013481Sgiacomo.travaglini@arm.com``` 73113481Sgiacomo.travaglini@arm.com 73213481Sgiacomo.travaglini@arm.comYou can do this in `main()` to set the style for all death tests in the 73313481Sgiacomo.travaglini@arm.combinary, or in individual tests. Recall that flags are saved before running each 73413481Sgiacomo.travaglini@arm.comtest and restored afterwards, so you need not do that yourself. For example: 73513481Sgiacomo.travaglini@arm.com 73613481Sgiacomo.travaglini@arm.com``` 73713481Sgiacomo.travaglini@arm.comTEST(MyDeathTest, TestOne) { 73813481Sgiacomo.travaglini@arm.com ::testing::FLAGS_gtest_death_test_style = "threadsafe"; 73913481Sgiacomo.travaglini@arm.com // This test is run in the "threadsafe" style: 74013481Sgiacomo.travaglini@arm.com ASSERT_DEATH(ThisShouldDie(), ""); 74113481Sgiacomo.travaglini@arm.com} 74213481Sgiacomo.travaglini@arm.com 74313481Sgiacomo.travaglini@arm.comTEST(MyDeathTest, TestTwo) { 74413481Sgiacomo.travaglini@arm.com // This test is run in the "fast" style: 74513481Sgiacomo.travaglini@arm.com ASSERT_DEATH(ThisShouldDie(), ""); 74613481Sgiacomo.travaglini@arm.com} 74713481Sgiacomo.travaglini@arm.com 74813481Sgiacomo.travaglini@arm.comint main(int argc, char** argv) { 74913481Sgiacomo.travaglini@arm.com ::testing::InitGoogleTest(&argc, argv); 75013481Sgiacomo.travaglini@arm.com ::testing::FLAGS_gtest_death_test_style = "fast"; 75113481Sgiacomo.travaglini@arm.com return RUN_ALL_TESTS(); 75213481Sgiacomo.travaglini@arm.com} 75313481Sgiacomo.travaglini@arm.com``` 75413481Sgiacomo.travaglini@arm.com 75513481Sgiacomo.travaglini@arm.com## Caveats ## 75613481Sgiacomo.travaglini@arm.com 75713481Sgiacomo.travaglini@arm.comThe _statement_ argument of `ASSERT_EXIT()` can be any valid C++ statement. 75813481Sgiacomo.travaglini@arm.comIf it leaves the current function via a `return` statement or by throwing an exception, 75913481Sgiacomo.travaglini@arm.comthe death test is considered to have failed. Some Google Test macros may return 76013481Sgiacomo.travaglini@arm.comfrom the current function (e.g. `ASSERT_TRUE()`), so be sure to avoid them in _statement_. 76113481Sgiacomo.travaglini@arm.com 76213481Sgiacomo.travaglini@arm.comSince _statement_ runs in the child process, any in-memory side effect (e.g. 76313481Sgiacomo.travaglini@arm.commodifying a variable, releasing memory, etc) it causes will _not_ be observable 76413481Sgiacomo.travaglini@arm.comin the parent process. In particular, if you release memory in a death test, 76513481Sgiacomo.travaglini@arm.comyour program will fail the heap check as the parent process will never see the 76613481Sgiacomo.travaglini@arm.commemory reclaimed. To solve this problem, you can 76713481Sgiacomo.travaglini@arm.com 76813481Sgiacomo.travaglini@arm.com 1. try not to free memory in a death test; 76913481Sgiacomo.travaglini@arm.com 1. free the memory again in the parent process; or 77013481Sgiacomo.travaglini@arm.com 1. do not use the heap checker in your program. 77113481Sgiacomo.travaglini@arm.com 77213481Sgiacomo.travaglini@arm.comDue to an implementation detail, you cannot place multiple death test 77313481Sgiacomo.travaglini@arm.comassertions on the same line; otherwise, compilation will fail with an unobvious 77413481Sgiacomo.travaglini@arm.comerror message. 77513481Sgiacomo.travaglini@arm.com 77613481Sgiacomo.travaglini@arm.comDespite the improved thread safety afforded by the "threadsafe" style of death 77713481Sgiacomo.travaglini@arm.comtest, thread problems such as deadlock are still possible in the presence of 77813481Sgiacomo.travaglini@arm.comhandlers registered with `pthread_atfork(3)`. 77913481Sgiacomo.travaglini@arm.com 78013481Sgiacomo.travaglini@arm.com# Using Assertions in Sub-routines # 78113481Sgiacomo.travaglini@arm.com 78213481Sgiacomo.travaglini@arm.com## Adding Traces to Assertions ## 78313481Sgiacomo.travaglini@arm.com 78413481Sgiacomo.travaglini@arm.comIf a test sub-routine is called from several places, when an assertion 78513481Sgiacomo.travaglini@arm.cominside it fails, it can be hard to tell which invocation of the 78613481Sgiacomo.travaglini@arm.comsub-routine the failure is from. You can alleviate this problem using 78713481Sgiacomo.travaglini@arm.comextra logging or custom failure messages, but that usually clutters up 78813481Sgiacomo.travaglini@arm.comyour tests. A better solution is to use the `SCOPED_TRACE` macro: 78913481Sgiacomo.travaglini@arm.com 79013481Sgiacomo.travaglini@arm.com| `SCOPED_TRACE(`_message_`);` | 79113481Sgiacomo.travaglini@arm.com|:-----------------------------| 79213481Sgiacomo.travaglini@arm.com 79313481Sgiacomo.travaglini@arm.comwhere _message_ can be anything streamable to `std::ostream`. This 79413481Sgiacomo.travaglini@arm.commacro will cause the current file name, line number, and the given 79513481Sgiacomo.travaglini@arm.commessage to be added in every failure message. The effect will be 79613481Sgiacomo.travaglini@arm.comundone when the control leaves the current lexical scope. 79713481Sgiacomo.travaglini@arm.com 79813481Sgiacomo.travaglini@arm.comFor example, 79913481Sgiacomo.travaglini@arm.com 80013481Sgiacomo.travaglini@arm.com``` 80113481Sgiacomo.travaglini@arm.com10: void Sub1(int n) { 80213481Sgiacomo.travaglini@arm.com11: EXPECT_EQ(1, Bar(n)); 80313481Sgiacomo.travaglini@arm.com12: EXPECT_EQ(2, Bar(n + 1)); 80413481Sgiacomo.travaglini@arm.com13: } 80513481Sgiacomo.travaglini@arm.com14: 80613481Sgiacomo.travaglini@arm.com15: TEST(FooTest, Bar) { 80713481Sgiacomo.travaglini@arm.com16: { 80813481Sgiacomo.travaglini@arm.com17: SCOPED_TRACE("A"); // This trace point will be included in 80913481Sgiacomo.travaglini@arm.com18: // every failure in this scope. 81013481Sgiacomo.travaglini@arm.com19: Sub1(1); 81113481Sgiacomo.travaglini@arm.com20: } 81213481Sgiacomo.travaglini@arm.com21: // Now it won't. 81313481Sgiacomo.travaglini@arm.com22: Sub1(9); 81413481Sgiacomo.travaglini@arm.com23: } 81513481Sgiacomo.travaglini@arm.com``` 81613481Sgiacomo.travaglini@arm.com 81713481Sgiacomo.travaglini@arm.comcould result in messages like these: 81813481Sgiacomo.travaglini@arm.com 81913481Sgiacomo.travaglini@arm.com``` 82013481Sgiacomo.travaglini@arm.compath/to/foo_test.cc:11: Failure 82113481Sgiacomo.travaglini@arm.comValue of: Bar(n) 82213481Sgiacomo.travaglini@arm.comExpected: 1 82313481Sgiacomo.travaglini@arm.com Actual: 2 82413481Sgiacomo.travaglini@arm.com Trace: 82513481Sgiacomo.travaglini@arm.compath/to/foo_test.cc:17: A 82613481Sgiacomo.travaglini@arm.com 82713481Sgiacomo.travaglini@arm.compath/to/foo_test.cc:12: Failure 82813481Sgiacomo.travaglini@arm.comValue of: Bar(n + 1) 82913481Sgiacomo.travaglini@arm.comExpected: 2 83013481Sgiacomo.travaglini@arm.com Actual: 3 83113481Sgiacomo.travaglini@arm.com``` 83213481Sgiacomo.travaglini@arm.com 83313481Sgiacomo.travaglini@arm.comWithout the trace, it would've been difficult to know which invocation 83413481Sgiacomo.travaglini@arm.comof `Sub1()` the two failures come from respectively. (You could add an 83513481Sgiacomo.travaglini@arm.comextra message to each assertion in `Sub1()` to indicate the value of 83613481Sgiacomo.travaglini@arm.com`n`, but that's tedious.) 83713481Sgiacomo.travaglini@arm.com 83813481Sgiacomo.travaglini@arm.comSome tips on using `SCOPED_TRACE`: 83913481Sgiacomo.travaglini@arm.com 84013481Sgiacomo.travaglini@arm.com 1. With a suitable message, it's often enough to use `SCOPED_TRACE` at the beginning of a sub-routine, instead of at each call site. 84113481Sgiacomo.travaglini@arm.com 1. When calling sub-routines inside a loop, make the loop iterator part of the message in `SCOPED_TRACE` such that you can know which iteration the failure is from. 84213481Sgiacomo.travaglini@arm.com 1. Sometimes the line number of the trace point is enough for identifying the particular invocation of a sub-routine. In this case, you don't have to choose a unique message for `SCOPED_TRACE`. You can simply use `""`. 84313481Sgiacomo.travaglini@arm.com 1. You can use `SCOPED_TRACE` in an inner scope when there is one in the outer scope. In this case, all active trace points will be included in the failure messages, in reverse order they are encountered. 84413481Sgiacomo.travaglini@arm.com 1. The trace dump is clickable in Emacs' compilation buffer - hit return on a line number and you'll be taken to that line in the source file! 84513481Sgiacomo.travaglini@arm.com 84613481Sgiacomo.travaglini@arm.com_Availability:_ Linux, Windows, Mac. 84713481Sgiacomo.travaglini@arm.com 84813481Sgiacomo.travaglini@arm.com## Propagating Fatal Failures ## 84913481Sgiacomo.travaglini@arm.com 85013481Sgiacomo.travaglini@arm.comA common pitfall when using `ASSERT_*` and `FAIL*` is not understanding that 85113481Sgiacomo.travaglini@arm.comwhen they fail they only abort the _current function_, not the entire test. For 85213481Sgiacomo.travaglini@arm.comexample, the following test will segfault: 85313481Sgiacomo.travaglini@arm.com``` 85413481Sgiacomo.travaglini@arm.comvoid Subroutine() { 85513481Sgiacomo.travaglini@arm.com // Generates a fatal failure and aborts the current function. 85613481Sgiacomo.travaglini@arm.com ASSERT_EQ(1, 2); 85713481Sgiacomo.travaglini@arm.com // The following won't be executed. 85813481Sgiacomo.travaglini@arm.com ... 85913481Sgiacomo.travaglini@arm.com} 86013481Sgiacomo.travaglini@arm.com 86113481Sgiacomo.travaglini@arm.comTEST(FooTest, Bar) { 86213481Sgiacomo.travaglini@arm.com Subroutine(); 86313481Sgiacomo.travaglini@arm.com // The intended behavior is for the fatal failure 86413481Sgiacomo.travaglini@arm.com // in Subroutine() to abort the entire test. 86513481Sgiacomo.travaglini@arm.com // The actual behavior: the function goes on after Subroutine() returns. 86613481Sgiacomo.travaglini@arm.com int* p = NULL; 86713481Sgiacomo.travaglini@arm.com *p = 3; // Segfault! 86813481Sgiacomo.travaglini@arm.com} 86913481Sgiacomo.travaglini@arm.com``` 87013481Sgiacomo.travaglini@arm.com 87113481Sgiacomo.travaglini@arm.comSince we don't use exceptions, it is technically impossible to 87213481Sgiacomo.travaglini@arm.comimplement the intended behavior here. To alleviate this, Google Test 87313481Sgiacomo.travaglini@arm.comprovides two solutions. You could use either the 87413481Sgiacomo.travaglini@arm.com`(ASSERT|EXPECT)_NO_FATAL_FAILURE` assertions or the 87513481Sgiacomo.travaglini@arm.com`HasFatalFailure()` function. They are described in the following two 87613481Sgiacomo.travaglini@arm.comsubsections. 87713481Sgiacomo.travaglini@arm.com 87813481Sgiacomo.travaglini@arm.com### Asserting on Subroutines ### 87913481Sgiacomo.travaglini@arm.com 88013481Sgiacomo.travaglini@arm.comAs shown above, if your test calls a subroutine that has an `ASSERT_*` 88113481Sgiacomo.travaglini@arm.comfailure in it, the test will continue after the subroutine 88213481Sgiacomo.travaglini@arm.comreturns. This may not be what you want. 88313481Sgiacomo.travaglini@arm.com 88413481Sgiacomo.travaglini@arm.comOften people want fatal failures to propagate like exceptions. For 88513481Sgiacomo.travaglini@arm.comthat Google Test offers the following macros: 88613481Sgiacomo.travaglini@arm.com 88713481Sgiacomo.travaglini@arm.com| **Fatal assertion** | **Nonfatal assertion** | **Verifies** | 88813481Sgiacomo.travaglini@arm.com|:--------------------|:-----------------------|:-------------| 88913481Sgiacomo.travaglini@arm.com| `ASSERT_NO_FATAL_FAILURE(`_statement_`);` | `EXPECT_NO_FATAL_FAILURE(`_statement_`);` | _statement_ doesn't generate any new fatal failures in the current thread. | 89013481Sgiacomo.travaglini@arm.com 89113481Sgiacomo.travaglini@arm.comOnly failures in the thread that executes the assertion are checked to 89213481Sgiacomo.travaglini@arm.comdetermine the result of this type of assertions. If _statement_ 89313481Sgiacomo.travaglini@arm.comcreates new threads, failures in these threads are ignored. 89413481Sgiacomo.travaglini@arm.com 89513481Sgiacomo.travaglini@arm.comExamples: 89613481Sgiacomo.travaglini@arm.com 89713481Sgiacomo.travaglini@arm.com``` 89813481Sgiacomo.travaglini@arm.comASSERT_NO_FATAL_FAILURE(Foo()); 89913481Sgiacomo.travaglini@arm.com 90013481Sgiacomo.travaglini@arm.comint i; 90113481Sgiacomo.travaglini@arm.comEXPECT_NO_FATAL_FAILURE({ 90213481Sgiacomo.travaglini@arm.com i = Bar(); 90313481Sgiacomo.travaglini@arm.com}); 90413481Sgiacomo.travaglini@arm.com``` 90513481Sgiacomo.travaglini@arm.com 90613481Sgiacomo.travaglini@arm.com_Availability:_ Linux, Windows, Mac. Assertions from multiple threads 90713481Sgiacomo.travaglini@arm.comare currently not supported. 90813481Sgiacomo.travaglini@arm.com 90913481Sgiacomo.travaglini@arm.com### Checking for Failures in the Current Test ### 91013481Sgiacomo.travaglini@arm.com 91113481Sgiacomo.travaglini@arm.com`HasFatalFailure()` in the `::testing::Test` class returns `true` if an 91213481Sgiacomo.travaglini@arm.comassertion in the current test has suffered a fatal failure. This 91313481Sgiacomo.travaglini@arm.comallows functions to catch fatal failures in a sub-routine and return 91413481Sgiacomo.travaglini@arm.comearly. 91513481Sgiacomo.travaglini@arm.com 91613481Sgiacomo.travaglini@arm.com``` 91713481Sgiacomo.travaglini@arm.comclass Test { 91813481Sgiacomo.travaglini@arm.com public: 91913481Sgiacomo.travaglini@arm.com ... 92013481Sgiacomo.travaglini@arm.com static bool HasFatalFailure(); 92113481Sgiacomo.travaglini@arm.com}; 92213481Sgiacomo.travaglini@arm.com``` 92313481Sgiacomo.travaglini@arm.com 92413481Sgiacomo.travaglini@arm.comThe typical usage, which basically simulates the behavior of a thrown 92513481Sgiacomo.travaglini@arm.comexception, is: 92613481Sgiacomo.travaglini@arm.com 92713481Sgiacomo.travaglini@arm.com``` 92813481Sgiacomo.travaglini@arm.comTEST(FooTest, Bar) { 92913481Sgiacomo.travaglini@arm.com Subroutine(); 93013481Sgiacomo.travaglini@arm.com // Aborts if Subroutine() had a fatal failure. 93113481Sgiacomo.travaglini@arm.com if (HasFatalFailure()) 93213481Sgiacomo.travaglini@arm.com return; 93313481Sgiacomo.travaglini@arm.com // The following won't be executed. 93413481Sgiacomo.travaglini@arm.com ... 93513481Sgiacomo.travaglini@arm.com} 93613481Sgiacomo.travaglini@arm.com``` 93713481Sgiacomo.travaglini@arm.com 93813481Sgiacomo.travaglini@arm.comIf `HasFatalFailure()` is used outside of `TEST()` , `TEST_F()` , or a test 93913481Sgiacomo.travaglini@arm.comfixture, you must add the `::testing::Test::` prefix, as in: 94013481Sgiacomo.travaglini@arm.com 94113481Sgiacomo.travaglini@arm.com``` 94213481Sgiacomo.travaglini@arm.comif (::testing::Test::HasFatalFailure()) 94313481Sgiacomo.travaglini@arm.com return; 94413481Sgiacomo.travaglini@arm.com``` 94513481Sgiacomo.travaglini@arm.com 94613481Sgiacomo.travaglini@arm.comSimilarly, `HasNonfatalFailure()` returns `true` if the current test 94713481Sgiacomo.travaglini@arm.comhas at least one non-fatal failure, and `HasFailure()` returns `true` 94813481Sgiacomo.travaglini@arm.comif the current test has at least one failure of either kind. 94913481Sgiacomo.travaglini@arm.com 95013481Sgiacomo.travaglini@arm.com_Availability:_ Linux, Windows, Mac. `HasNonfatalFailure()` and 95113481Sgiacomo.travaglini@arm.com`HasFailure()` are available since version 1.4.0. 95213481Sgiacomo.travaglini@arm.com 95313481Sgiacomo.travaglini@arm.com# Logging Additional Information # 95413481Sgiacomo.travaglini@arm.com 95513481Sgiacomo.travaglini@arm.comIn your test code, you can call `RecordProperty("key", value)` to log 95613481Sgiacomo.travaglini@arm.comadditional information, where `value` can be either a string or an `int`. The _last_ value recorded for a key will be emitted to the XML output 95713481Sgiacomo.travaglini@arm.comif you specify one. For example, the test 95813481Sgiacomo.travaglini@arm.com 95913481Sgiacomo.travaglini@arm.com``` 96013481Sgiacomo.travaglini@arm.comTEST_F(WidgetUsageTest, MinAndMaxWidgets) { 96113481Sgiacomo.travaglini@arm.com RecordProperty("MaximumWidgets", ComputeMaxUsage()); 96213481Sgiacomo.travaglini@arm.com RecordProperty("MinimumWidgets", ComputeMinUsage()); 96313481Sgiacomo.travaglini@arm.com} 96413481Sgiacomo.travaglini@arm.com``` 96513481Sgiacomo.travaglini@arm.com 96613481Sgiacomo.travaglini@arm.comwill output XML like this: 96713481Sgiacomo.travaglini@arm.com 96813481Sgiacomo.travaglini@arm.com``` 96913481Sgiacomo.travaglini@arm.com... 97013481Sgiacomo.travaglini@arm.com <testcase name="MinAndMaxWidgets" status="run" time="6" classname="WidgetUsageTest" 97113481Sgiacomo.travaglini@arm.com MaximumWidgets="12" 97213481Sgiacomo.travaglini@arm.com MinimumWidgets="9" /> 97313481Sgiacomo.travaglini@arm.com... 97413481Sgiacomo.travaglini@arm.com``` 97513481Sgiacomo.travaglini@arm.com 97613481Sgiacomo.travaglini@arm.com_Note_: 97713481Sgiacomo.travaglini@arm.com * `RecordProperty()` is a static member of the `Test` class. Therefore it needs to be prefixed with `::testing::Test::` if used outside of the `TEST` body and the test fixture class. 97813481Sgiacomo.travaglini@arm.com * `key` must be a valid XML attribute name, and cannot conflict with the ones already used by Google Test (`name`, `status`, `time`, `classname`, `type_param`, and `value_param`). 97913481Sgiacomo.travaglini@arm.com * Calling `RecordProperty()` outside of the lifespan of a test is allowed. If it's called outside of a test but between a test case's `SetUpTestCase()` and `TearDownTestCase()` methods, it will be attributed to the XML element for the test case. If it's called outside of all test cases (e.g. in a test environment), it will be attributed to the top-level XML element. 98013481Sgiacomo.travaglini@arm.com 98113481Sgiacomo.travaglini@arm.com_Availability_: Linux, Windows, Mac. 98213481Sgiacomo.travaglini@arm.com 98313481Sgiacomo.travaglini@arm.com# Sharing Resources Between Tests in the Same Test Case # 98413481Sgiacomo.travaglini@arm.com 98513481Sgiacomo.travaglini@arm.com 98613481Sgiacomo.travaglini@arm.com 98713481Sgiacomo.travaglini@arm.comGoogle Test creates a new test fixture object for each test in order to make 98813481Sgiacomo.travaglini@arm.comtests independent and easier to debug. However, sometimes tests use resources 98913481Sgiacomo.travaglini@arm.comthat are expensive to set up, making the one-copy-per-test model prohibitively 99013481Sgiacomo.travaglini@arm.comexpensive. 99113481Sgiacomo.travaglini@arm.com 99213481Sgiacomo.travaglini@arm.comIf the tests don't change the resource, there's no harm in them sharing a 99313481Sgiacomo.travaglini@arm.comsingle resource copy. So, in addition to per-test set-up/tear-down, Google Test 99413481Sgiacomo.travaglini@arm.comalso supports per-test-case set-up/tear-down. To use it: 99513481Sgiacomo.travaglini@arm.com 99613481Sgiacomo.travaglini@arm.com 1. In your test fixture class (say `FooTest` ), define as `static` some member variables to hold the shared resources. 99713481Sgiacomo.travaglini@arm.com 1. In the same test fixture class, define a `static void SetUpTestCase()` function (remember not to spell it as **`SetupTestCase`** with a small `u`!) to set up the shared resources and a `static void TearDownTestCase()` function to tear them down. 99813481Sgiacomo.travaglini@arm.com 99913481Sgiacomo.travaglini@arm.comThat's it! Google Test automatically calls `SetUpTestCase()` before running the 100013481Sgiacomo.travaglini@arm.com_first test_ in the `FooTest` test case (i.e. before creating the first 100113481Sgiacomo.travaglini@arm.com`FooTest` object), and calls `TearDownTestCase()` after running the _last test_ 100213481Sgiacomo.travaglini@arm.comin it (i.e. after deleting the last `FooTest` object). In between, the tests 100313481Sgiacomo.travaglini@arm.comcan use the shared resources. 100413481Sgiacomo.travaglini@arm.com 100513481Sgiacomo.travaglini@arm.comRemember that the test order is undefined, so your code can't depend on a test 100613481Sgiacomo.travaglini@arm.compreceding or following another. Also, the tests must either not modify the 100713481Sgiacomo.travaglini@arm.comstate of any shared resource, or, if they do modify the state, they must 100813481Sgiacomo.travaglini@arm.comrestore the state to its original value before passing control to the next 100913481Sgiacomo.travaglini@arm.comtest. 101013481Sgiacomo.travaglini@arm.com 101113481Sgiacomo.travaglini@arm.comHere's an example of per-test-case set-up and tear-down: 101213481Sgiacomo.travaglini@arm.com``` 101313481Sgiacomo.travaglini@arm.comclass FooTest : public ::testing::Test { 101413481Sgiacomo.travaglini@arm.com protected: 101513481Sgiacomo.travaglini@arm.com // Per-test-case set-up. 101613481Sgiacomo.travaglini@arm.com // Called before the first test in this test case. 101713481Sgiacomo.travaglini@arm.com // Can be omitted if not needed. 101813481Sgiacomo.travaglini@arm.com static void SetUpTestCase() { 101913481Sgiacomo.travaglini@arm.com shared_resource_ = new ...; 102013481Sgiacomo.travaglini@arm.com } 102113481Sgiacomo.travaglini@arm.com 102213481Sgiacomo.travaglini@arm.com // Per-test-case tear-down. 102313481Sgiacomo.travaglini@arm.com // Called after the last test in this test case. 102413481Sgiacomo.travaglini@arm.com // Can be omitted if not needed. 102513481Sgiacomo.travaglini@arm.com static void TearDownTestCase() { 102613481Sgiacomo.travaglini@arm.com delete shared_resource_; 102713481Sgiacomo.travaglini@arm.com shared_resource_ = NULL; 102813481Sgiacomo.travaglini@arm.com } 102913481Sgiacomo.travaglini@arm.com 103013481Sgiacomo.travaglini@arm.com // You can define per-test set-up and tear-down logic as usual. 103113481Sgiacomo.travaglini@arm.com virtual void SetUp() { ... } 103213481Sgiacomo.travaglini@arm.com virtual void TearDown() { ... } 103313481Sgiacomo.travaglini@arm.com 103413481Sgiacomo.travaglini@arm.com // Some expensive resource shared by all tests. 103513481Sgiacomo.travaglini@arm.com static T* shared_resource_; 103613481Sgiacomo.travaglini@arm.com}; 103713481Sgiacomo.travaglini@arm.com 103813481Sgiacomo.travaglini@arm.comT* FooTest::shared_resource_ = NULL; 103913481Sgiacomo.travaglini@arm.com 104013481Sgiacomo.travaglini@arm.comTEST_F(FooTest, Test1) { 104113481Sgiacomo.travaglini@arm.com ... you can refer to shared_resource here ... 104213481Sgiacomo.travaglini@arm.com} 104313481Sgiacomo.travaglini@arm.comTEST_F(FooTest, Test2) { 104413481Sgiacomo.travaglini@arm.com ... you can refer to shared_resource here ... 104513481Sgiacomo.travaglini@arm.com} 104613481Sgiacomo.travaglini@arm.com``` 104713481Sgiacomo.travaglini@arm.com 104813481Sgiacomo.travaglini@arm.com_Availability:_ Linux, Windows, Mac. 104913481Sgiacomo.travaglini@arm.com 105013481Sgiacomo.travaglini@arm.com# Global Set-Up and Tear-Down # 105113481Sgiacomo.travaglini@arm.com 105213481Sgiacomo.travaglini@arm.comJust as you can do set-up and tear-down at the test level and the test case 105313481Sgiacomo.travaglini@arm.comlevel, you can also do it at the test program level. Here's how. 105413481Sgiacomo.travaglini@arm.com 105513481Sgiacomo.travaglini@arm.comFirst, you subclass the `::testing::Environment` class to define a test 105613481Sgiacomo.travaglini@arm.comenvironment, which knows how to set-up and tear-down: 105713481Sgiacomo.travaglini@arm.com 105813481Sgiacomo.travaglini@arm.com``` 105913481Sgiacomo.travaglini@arm.comclass Environment { 106013481Sgiacomo.travaglini@arm.com public: 106113481Sgiacomo.travaglini@arm.com virtual ~Environment() {} 106213481Sgiacomo.travaglini@arm.com // Override this to define how to set up the environment. 106313481Sgiacomo.travaglini@arm.com virtual void SetUp() {} 106413481Sgiacomo.travaglini@arm.com // Override this to define how to tear down the environment. 106513481Sgiacomo.travaglini@arm.com virtual void TearDown() {} 106613481Sgiacomo.travaglini@arm.com}; 106713481Sgiacomo.travaglini@arm.com``` 106813481Sgiacomo.travaglini@arm.com 106913481Sgiacomo.travaglini@arm.comThen, you register an instance of your environment class with Google Test by 107013481Sgiacomo.travaglini@arm.comcalling the `::testing::AddGlobalTestEnvironment()` function: 107113481Sgiacomo.travaglini@arm.com 107213481Sgiacomo.travaglini@arm.com``` 107313481Sgiacomo.travaglini@arm.comEnvironment* AddGlobalTestEnvironment(Environment* env); 107413481Sgiacomo.travaglini@arm.com``` 107513481Sgiacomo.travaglini@arm.com 107613481Sgiacomo.travaglini@arm.comNow, when `RUN_ALL_TESTS()` is called, it first calls the `SetUp()` method of 107713481Sgiacomo.travaglini@arm.comthe environment object, then runs the tests if there was no fatal failures, and 107813481Sgiacomo.travaglini@arm.comfinally calls `TearDown()` of the environment object. 107913481Sgiacomo.travaglini@arm.com 108013481Sgiacomo.travaglini@arm.comIt's OK to register multiple environment objects. In this case, their `SetUp()` 108113481Sgiacomo.travaglini@arm.comwill be called in the order they are registered, and their `TearDown()` will be 108213481Sgiacomo.travaglini@arm.comcalled in the reverse order. 108313481Sgiacomo.travaglini@arm.com 108413481Sgiacomo.travaglini@arm.comNote that Google Test takes ownership of the registered environment objects. 108513481Sgiacomo.travaglini@arm.comTherefore **do not delete them** by yourself. 108613481Sgiacomo.travaglini@arm.com 108713481Sgiacomo.travaglini@arm.comYou should call `AddGlobalTestEnvironment()` before `RUN_ALL_TESTS()` is 108813481Sgiacomo.travaglini@arm.comcalled, probably in `main()`. If you use `gtest_main`, you need to call 108913481Sgiacomo.travaglini@arm.comthis before `main()` starts for it to take effect. One way to do this is to 109013481Sgiacomo.travaglini@arm.comdefine a global variable like this: 109113481Sgiacomo.travaglini@arm.com 109213481Sgiacomo.travaglini@arm.com``` 109313481Sgiacomo.travaglini@arm.com::testing::Environment* const foo_env = ::testing::AddGlobalTestEnvironment(new FooEnvironment); 109413481Sgiacomo.travaglini@arm.com``` 109513481Sgiacomo.travaglini@arm.com 109613481Sgiacomo.travaglini@arm.comHowever, we strongly recommend you to write your own `main()` and call 109713481Sgiacomo.travaglini@arm.com`AddGlobalTestEnvironment()` there, as relying on initialization of global 109813481Sgiacomo.travaglini@arm.comvariables makes the code harder to read and may cause problems when you 109913481Sgiacomo.travaglini@arm.comregister multiple environments from different translation units and the 110013481Sgiacomo.travaglini@arm.comenvironments have dependencies among them (remember that the compiler doesn't 110113481Sgiacomo.travaglini@arm.comguarantee the order in which global variables from different translation units 110213481Sgiacomo.travaglini@arm.comare initialized). 110313481Sgiacomo.travaglini@arm.com 110413481Sgiacomo.travaglini@arm.com_Availability:_ Linux, Windows, Mac. 110513481Sgiacomo.travaglini@arm.com 110613481Sgiacomo.travaglini@arm.com 110713481Sgiacomo.travaglini@arm.com# Value Parameterized Tests # 110813481Sgiacomo.travaglini@arm.com 110913481Sgiacomo.travaglini@arm.com_Value-parameterized tests_ allow you to test your code with different 111013481Sgiacomo.travaglini@arm.comparameters without writing multiple copies of the same test. 111113481Sgiacomo.travaglini@arm.com 111213481Sgiacomo.travaglini@arm.comSuppose you write a test for your code and then realize that your code is affected by a presence of a Boolean command line flag. 111313481Sgiacomo.travaglini@arm.com 111413481Sgiacomo.travaglini@arm.com``` 111513481Sgiacomo.travaglini@arm.comTEST(MyCodeTest, TestFoo) { 111613481Sgiacomo.travaglini@arm.com // A code to test foo(). 111713481Sgiacomo.travaglini@arm.com} 111813481Sgiacomo.travaglini@arm.com``` 111913481Sgiacomo.travaglini@arm.com 112013481Sgiacomo.travaglini@arm.comUsually people factor their test code into a function with a Boolean parameter in such situations. The function sets the flag, then executes the testing code. 112113481Sgiacomo.travaglini@arm.com 112213481Sgiacomo.travaglini@arm.com``` 112313481Sgiacomo.travaglini@arm.comvoid TestFooHelper(bool flag_value) { 112413481Sgiacomo.travaglini@arm.com flag = flag_value; 112513481Sgiacomo.travaglini@arm.com // A code to test foo(). 112613481Sgiacomo.travaglini@arm.com} 112713481Sgiacomo.travaglini@arm.com 112813481Sgiacomo.travaglini@arm.comTEST(MyCodeTest, TestFoo) { 112913481Sgiacomo.travaglini@arm.com TestFooHelper(false); 113013481Sgiacomo.travaglini@arm.com TestFooHelper(true); 113113481Sgiacomo.travaglini@arm.com} 113213481Sgiacomo.travaglini@arm.com``` 113313481Sgiacomo.travaglini@arm.com 113413481Sgiacomo.travaglini@arm.comBut this setup has serious drawbacks. First, when a test assertion fails in your tests, it becomes unclear what value of the parameter caused it to fail. You can stream a clarifying message into your `EXPECT`/`ASSERT` statements, but it you'll have to do it with all of them. Second, you have to add one such helper function per test. What if you have ten tests? Twenty? A hundred? 113513481Sgiacomo.travaglini@arm.com 113613481Sgiacomo.travaglini@arm.comValue-parameterized tests will let you write your test only once and then easily instantiate and run it with an arbitrary number of parameter values. 113713481Sgiacomo.travaglini@arm.com 113813481Sgiacomo.travaglini@arm.comHere are some other situations when value-parameterized tests come handy: 113913481Sgiacomo.travaglini@arm.com 114013481Sgiacomo.travaglini@arm.com * You want to test different implementations of an OO interface. 114113481Sgiacomo.travaglini@arm.com * You want to test your code over various inputs (a.k.a. data-driven testing). This feature is easy to abuse, so please exercise your good sense when doing it! 114213481Sgiacomo.travaglini@arm.com 114313481Sgiacomo.travaglini@arm.com## How to Write Value-Parameterized Tests ## 114413481Sgiacomo.travaglini@arm.com 114513481Sgiacomo.travaglini@arm.comTo write value-parameterized tests, first you should define a fixture 114613481Sgiacomo.travaglini@arm.comclass. It must be derived from both `::testing::Test` and 114713481Sgiacomo.travaglini@arm.com`::testing::WithParamInterface<T>` (the latter is a pure interface), 114813481Sgiacomo.travaglini@arm.comwhere `T` is the type of your parameter values. For convenience, you 114913481Sgiacomo.travaglini@arm.comcan just derive the fixture class from `::testing::TestWithParam<T>`, 115013481Sgiacomo.travaglini@arm.comwhich itself is derived from both `::testing::Test` and 115113481Sgiacomo.travaglini@arm.com`::testing::WithParamInterface<T>`. `T` can be any copyable type. If 115213481Sgiacomo.travaglini@arm.comit's a raw pointer, you are responsible for managing the lifespan of 115313481Sgiacomo.travaglini@arm.comthe pointed values. 115413481Sgiacomo.travaglini@arm.com 115513481Sgiacomo.travaglini@arm.com``` 115613481Sgiacomo.travaglini@arm.comclass FooTest : public ::testing::TestWithParam<const char*> { 115713481Sgiacomo.travaglini@arm.com // You can implement all the usual fixture class members here. 115813481Sgiacomo.travaglini@arm.com // To access the test parameter, call GetParam() from class 115913481Sgiacomo.travaglini@arm.com // TestWithParam<T>. 116013481Sgiacomo.travaglini@arm.com}; 116113481Sgiacomo.travaglini@arm.com 116213481Sgiacomo.travaglini@arm.com// Or, when you want to add parameters to a pre-existing fixture class: 116313481Sgiacomo.travaglini@arm.comclass BaseTest : public ::testing::Test { 116413481Sgiacomo.travaglini@arm.com ... 116513481Sgiacomo.travaglini@arm.com}; 116613481Sgiacomo.travaglini@arm.comclass BarTest : public BaseTest, 116713481Sgiacomo.travaglini@arm.com public ::testing::WithParamInterface<const char*> { 116813481Sgiacomo.travaglini@arm.com ... 116913481Sgiacomo.travaglini@arm.com}; 117013481Sgiacomo.travaglini@arm.com``` 117113481Sgiacomo.travaglini@arm.com 117213481Sgiacomo.travaglini@arm.comThen, use the `TEST_P` macro to define as many test patterns using 117313481Sgiacomo.travaglini@arm.comthis fixture as you want. The `_P` suffix is for "parameterized" or 117413481Sgiacomo.travaglini@arm.com"pattern", whichever you prefer to think. 117513481Sgiacomo.travaglini@arm.com 117613481Sgiacomo.travaglini@arm.com``` 117713481Sgiacomo.travaglini@arm.comTEST_P(FooTest, DoesBlah) { 117813481Sgiacomo.travaglini@arm.com // Inside a test, access the test parameter with the GetParam() method 117913481Sgiacomo.travaglini@arm.com // of the TestWithParam<T> class: 118013481Sgiacomo.travaglini@arm.com EXPECT_TRUE(foo.Blah(GetParam())); 118113481Sgiacomo.travaglini@arm.com ... 118213481Sgiacomo.travaglini@arm.com} 118313481Sgiacomo.travaglini@arm.com 118413481Sgiacomo.travaglini@arm.comTEST_P(FooTest, HasBlahBlah) { 118513481Sgiacomo.travaglini@arm.com ... 118613481Sgiacomo.travaglini@arm.com} 118713481Sgiacomo.travaglini@arm.com``` 118813481Sgiacomo.travaglini@arm.com 118913481Sgiacomo.travaglini@arm.comFinally, you can use `INSTANTIATE_TEST_CASE_P` to instantiate the test 119013481Sgiacomo.travaglini@arm.comcase with any set of parameters you want. Google Test defines a number of 119113481Sgiacomo.travaglini@arm.comfunctions for generating test parameters. They return what we call 119213481Sgiacomo.travaglini@arm.com(surprise!) _parameter generators_. Here is a summary of them, 119313481Sgiacomo.travaglini@arm.comwhich are all in the `testing` namespace: 119413481Sgiacomo.travaglini@arm.com 119513481Sgiacomo.travaglini@arm.com| `Range(begin, end[, step])` | Yields values `{begin, begin+step, begin+step+step, ...}`. The values do not include `end`. `step` defaults to 1. | 119613481Sgiacomo.travaglini@arm.com|:----------------------------|:------------------------------------------------------------------------------------------------------------------| 119713481Sgiacomo.travaglini@arm.com| `Values(v1, v2, ..., vN)` | Yields values `{v1, v2, ..., vN}`. | 119813481Sgiacomo.travaglini@arm.com| `ValuesIn(container)` and `ValuesIn(begin, end)` | Yields values from a C-style array, an STL-style container, or an iterator range `[begin, end)`. `container`, `begin`, and `end` can be expressions whose values are determined at run time. | 119913481Sgiacomo.travaglini@arm.com| `Bool()` | Yields sequence `{false, true}`. | 120013481Sgiacomo.travaglini@arm.com| `Combine(g1, g2, ..., gN)` | Yields all combinations (the Cartesian product for the math savvy) of the values generated by the `N` generators. This is only available if your system provides the `<tr1/tuple>` header. If you are sure your system does, and Google Test disagrees, you can override it by defining `GTEST_HAS_TR1_TUPLE=1`. See comments in [include/gtest/internal/gtest-port.h](../include/gtest/internal/gtest-port.h) for more information. | 120113481Sgiacomo.travaglini@arm.com 120213481Sgiacomo.travaglini@arm.comFor more details, see the comments at the definitions of these functions in the [source code](../include/gtest/gtest-param-test.h). 120313481Sgiacomo.travaglini@arm.com 120413481Sgiacomo.travaglini@arm.comThe following statement will instantiate tests from the `FooTest` test case 120513481Sgiacomo.travaglini@arm.comeach with parameter values `"meeny"`, `"miny"`, and `"moe"`. 120613481Sgiacomo.travaglini@arm.com 120713481Sgiacomo.travaglini@arm.com``` 120813481Sgiacomo.travaglini@arm.comINSTANTIATE_TEST_CASE_P(InstantiationName, 120913481Sgiacomo.travaglini@arm.com FooTest, 121013481Sgiacomo.travaglini@arm.com ::testing::Values("meeny", "miny", "moe")); 121113481Sgiacomo.travaglini@arm.com``` 121213481Sgiacomo.travaglini@arm.com 121313481Sgiacomo.travaglini@arm.comTo distinguish different instances of the pattern (yes, you can 121413481Sgiacomo.travaglini@arm.cominstantiate it more than once), the first argument to 121513481Sgiacomo.travaglini@arm.com`INSTANTIATE_TEST_CASE_P` is a prefix that will be added to the actual 121613481Sgiacomo.travaglini@arm.comtest case name. Remember to pick unique prefixes for different 121713481Sgiacomo.travaglini@arm.cominstantiations. The tests from the instantiation above will have these 121813481Sgiacomo.travaglini@arm.comnames: 121913481Sgiacomo.travaglini@arm.com 122013481Sgiacomo.travaglini@arm.com * `InstantiationName/FooTest.DoesBlah/0` for `"meeny"` 122113481Sgiacomo.travaglini@arm.com * `InstantiationName/FooTest.DoesBlah/1` for `"miny"` 122213481Sgiacomo.travaglini@arm.com * `InstantiationName/FooTest.DoesBlah/2` for `"moe"` 122313481Sgiacomo.travaglini@arm.com * `InstantiationName/FooTest.HasBlahBlah/0` for `"meeny"` 122413481Sgiacomo.travaglini@arm.com * `InstantiationName/FooTest.HasBlahBlah/1` for `"miny"` 122513481Sgiacomo.travaglini@arm.com * `InstantiationName/FooTest.HasBlahBlah/2` for `"moe"` 122613481Sgiacomo.travaglini@arm.com 122713481Sgiacomo.travaglini@arm.comYou can use these names in [--gtest\_filter](#running-a-subset-of-the-tests). 122813481Sgiacomo.travaglini@arm.com 122913481Sgiacomo.travaglini@arm.comThis statement will instantiate all tests from `FooTest` again, each 123013481Sgiacomo.travaglini@arm.comwith parameter values `"cat"` and `"dog"`: 123113481Sgiacomo.travaglini@arm.com 123213481Sgiacomo.travaglini@arm.com``` 123313481Sgiacomo.travaglini@arm.comconst char* pets[] = {"cat", "dog"}; 123413481Sgiacomo.travaglini@arm.comINSTANTIATE_TEST_CASE_P(AnotherInstantiationName, FooTest, 123513481Sgiacomo.travaglini@arm.com ::testing::ValuesIn(pets)); 123613481Sgiacomo.travaglini@arm.com``` 123713481Sgiacomo.travaglini@arm.com 123813481Sgiacomo.travaglini@arm.comThe tests from the instantiation above will have these names: 123913481Sgiacomo.travaglini@arm.com 124013481Sgiacomo.travaglini@arm.com * `AnotherInstantiationName/FooTest.DoesBlah/0` for `"cat"` 124113481Sgiacomo.travaglini@arm.com * `AnotherInstantiationName/FooTest.DoesBlah/1` for `"dog"` 124213481Sgiacomo.travaglini@arm.com * `AnotherInstantiationName/FooTest.HasBlahBlah/0` for `"cat"` 124313481Sgiacomo.travaglini@arm.com * `AnotherInstantiationName/FooTest.HasBlahBlah/1` for `"dog"` 124413481Sgiacomo.travaglini@arm.com 124513481Sgiacomo.travaglini@arm.comPlease note that `INSTANTIATE_TEST_CASE_P` will instantiate _all_ 124613481Sgiacomo.travaglini@arm.comtests in the given test case, whether their definitions come before or 124713481Sgiacomo.travaglini@arm.com_after_ the `INSTANTIATE_TEST_CASE_P` statement. 124813481Sgiacomo.travaglini@arm.com 124913481Sgiacomo.travaglini@arm.comYou can see 125013481Sgiacomo.travaglini@arm.com[these](../samples/sample7_unittest.cc) 125113481Sgiacomo.travaglini@arm.com[files](../samples/sample8_unittest.cc) for more examples. 125213481Sgiacomo.travaglini@arm.com 125313481Sgiacomo.travaglini@arm.com_Availability_: Linux, Windows (requires MSVC 8.0 or above), Mac; since version 1.2.0. 125413481Sgiacomo.travaglini@arm.com 125513481Sgiacomo.travaglini@arm.com## Creating Value-Parameterized Abstract Tests ## 125613481Sgiacomo.travaglini@arm.com 125713481Sgiacomo.travaglini@arm.comIn the above, we define and instantiate `FooTest` in the same source 125813481Sgiacomo.travaglini@arm.comfile. Sometimes you may want to define value-parameterized tests in a 125913481Sgiacomo.travaglini@arm.comlibrary and let other people instantiate them later. This pattern is 126013481Sgiacomo.travaglini@arm.comknown as <i>abstract tests</i>. As an example of its application, when you 126113481Sgiacomo.travaglini@arm.comare designing an interface you can write a standard suite of abstract 126213481Sgiacomo.travaglini@arm.comtests (perhaps using a factory function as the test parameter) that 126313481Sgiacomo.travaglini@arm.comall implementations of the interface are expected to pass. When 126413481Sgiacomo.travaglini@arm.comsomeone implements the interface, he can instantiate your suite to get 126513481Sgiacomo.travaglini@arm.comall the interface-conformance tests for free. 126613481Sgiacomo.travaglini@arm.com 126713481Sgiacomo.travaglini@arm.comTo define abstract tests, you should organize your code like this: 126813481Sgiacomo.travaglini@arm.com 126913481Sgiacomo.travaglini@arm.com 1. Put the definition of the parameterized test fixture class (e.g. `FooTest`) in a header file, say `foo_param_test.h`. Think of this as _declaring_ your abstract tests. 127013481Sgiacomo.travaglini@arm.com 1. Put the `TEST_P` definitions in `foo_param_test.cc`, which includes `foo_param_test.h`. Think of this as _implementing_ your abstract tests. 127113481Sgiacomo.travaglini@arm.com 127213481Sgiacomo.travaglini@arm.comOnce they are defined, you can instantiate them by including 127313481Sgiacomo.travaglini@arm.com`foo_param_test.h`, invoking `INSTANTIATE_TEST_CASE_P()`, and linking 127413481Sgiacomo.travaglini@arm.comwith `foo_param_test.cc`. You can instantiate the same abstract test 127513481Sgiacomo.travaglini@arm.comcase multiple times, possibly in different source files. 127613481Sgiacomo.travaglini@arm.com 127713481Sgiacomo.travaglini@arm.com# Typed Tests # 127813481Sgiacomo.travaglini@arm.com 127913481Sgiacomo.travaglini@arm.comSuppose you have multiple implementations of the same interface and 128013481Sgiacomo.travaglini@arm.comwant to make sure that all of them satisfy some common requirements. 128113481Sgiacomo.travaglini@arm.comOr, you may have defined several types that are supposed to conform to 128213481Sgiacomo.travaglini@arm.comthe same "concept" and you want to verify it. In both cases, you want 128313481Sgiacomo.travaglini@arm.comthe same test logic repeated for different types. 128413481Sgiacomo.travaglini@arm.com 128513481Sgiacomo.travaglini@arm.comWhile you can write one `TEST` or `TEST_F` for each type you want to 128613481Sgiacomo.travaglini@arm.comtest (and you may even factor the test logic into a function template 128713481Sgiacomo.travaglini@arm.comthat you invoke from the `TEST`), it's tedious and doesn't scale: 128813481Sgiacomo.travaglini@arm.comif you want _m_ tests over _n_ types, you'll end up writing _m\*n_ 128913481Sgiacomo.travaglini@arm.com`TEST`s. 129013481Sgiacomo.travaglini@arm.com 129113481Sgiacomo.travaglini@arm.com_Typed tests_ allow you to repeat the same test logic over a list of 129213481Sgiacomo.travaglini@arm.comtypes. You only need to write the test logic once, although you must 129313481Sgiacomo.travaglini@arm.comknow the type list when writing typed tests. Here's how you do it: 129413481Sgiacomo.travaglini@arm.com 129513481Sgiacomo.travaglini@arm.comFirst, define a fixture class template. It should be parameterized 129613481Sgiacomo.travaglini@arm.comby a type. Remember to derive it from `::testing::Test`: 129713481Sgiacomo.travaglini@arm.com 129813481Sgiacomo.travaglini@arm.com``` 129913481Sgiacomo.travaglini@arm.comtemplate <typename T> 130013481Sgiacomo.travaglini@arm.comclass FooTest : public ::testing::Test { 130113481Sgiacomo.travaglini@arm.com public: 130213481Sgiacomo.travaglini@arm.com ... 130313481Sgiacomo.travaglini@arm.com typedef std::list<T> List; 130413481Sgiacomo.travaglini@arm.com static T shared_; 130513481Sgiacomo.travaglini@arm.com T value_; 130613481Sgiacomo.travaglini@arm.com}; 130713481Sgiacomo.travaglini@arm.com``` 130813481Sgiacomo.travaglini@arm.com 130913481Sgiacomo.travaglini@arm.comNext, associate a list of types with the test case, which will be 131013481Sgiacomo.travaglini@arm.comrepeated for each type in the list: 131113481Sgiacomo.travaglini@arm.com 131213481Sgiacomo.travaglini@arm.com``` 131313481Sgiacomo.travaglini@arm.comtypedef ::testing::Types<char, int, unsigned int> MyTypes; 131413481Sgiacomo.travaglini@arm.comTYPED_TEST_CASE(FooTest, MyTypes); 131513481Sgiacomo.travaglini@arm.com``` 131613481Sgiacomo.travaglini@arm.com 131713481Sgiacomo.travaglini@arm.comThe `typedef` is necessary for the `TYPED_TEST_CASE` macro to parse 131813481Sgiacomo.travaglini@arm.comcorrectly. Otherwise the compiler will think that each comma in the 131913481Sgiacomo.travaglini@arm.comtype list introduces a new macro argument. 132013481Sgiacomo.travaglini@arm.com 132113481Sgiacomo.travaglini@arm.comThen, use `TYPED_TEST()` instead of `TEST_F()` to define a typed test 132213481Sgiacomo.travaglini@arm.comfor this test case. You can repeat this as many times as you want: 132313481Sgiacomo.travaglini@arm.com 132413481Sgiacomo.travaglini@arm.com``` 132513481Sgiacomo.travaglini@arm.comTYPED_TEST(FooTest, DoesBlah) { 132613481Sgiacomo.travaglini@arm.com // Inside a test, refer to the special name TypeParam to get the type 132713481Sgiacomo.travaglini@arm.com // parameter. Since we are inside a derived class template, C++ requires 132813481Sgiacomo.travaglini@arm.com // us to visit the members of FooTest via 'this'. 132913481Sgiacomo.travaglini@arm.com TypeParam n = this->value_; 133013481Sgiacomo.travaglini@arm.com 133113481Sgiacomo.travaglini@arm.com // To visit static members of the fixture, add the 'TestFixture::' 133213481Sgiacomo.travaglini@arm.com // prefix. 133313481Sgiacomo.travaglini@arm.com n += TestFixture::shared_; 133413481Sgiacomo.travaglini@arm.com 133513481Sgiacomo.travaglini@arm.com // To refer to typedefs in the fixture, add the 'typename TestFixture::' 133613481Sgiacomo.travaglini@arm.com // prefix. The 'typename' is required to satisfy the compiler. 133713481Sgiacomo.travaglini@arm.com typename TestFixture::List values; 133813481Sgiacomo.travaglini@arm.com values.push_back(n); 133913481Sgiacomo.travaglini@arm.com ... 134013481Sgiacomo.travaglini@arm.com} 134113481Sgiacomo.travaglini@arm.com 134213481Sgiacomo.travaglini@arm.comTYPED_TEST(FooTest, HasPropertyA) { ... } 134313481Sgiacomo.travaglini@arm.com``` 134413481Sgiacomo.travaglini@arm.com 134513481Sgiacomo.travaglini@arm.comYou can see `samples/sample6_unittest.cc` for a complete example. 134613481Sgiacomo.travaglini@arm.com 134713481Sgiacomo.travaglini@arm.com_Availability:_ Linux, Windows (requires MSVC 8.0 or above), Mac; 134813481Sgiacomo.travaglini@arm.comsince version 1.1.0. 134913481Sgiacomo.travaglini@arm.com 135013481Sgiacomo.travaglini@arm.com# Type-Parameterized Tests # 135113481Sgiacomo.travaglini@arm.com 135213481Sgiacomo.travaglini@arm.com_Type-parameterized tests_ are like typed tests, except that they 135313481Sgiacomo.travaglini@arm.comdon't require you to know the list of types ahead of time. Instead, 135413481Sgiacomo.travaglini@arm.comyou can define the test logic first and instantiate it with different 135513481Sgiacomo.travaglini@arm.comtype lists later. You can even instantiate it more than once in the 135613481Sgiacomo.travaglini@arm.comsame program. 135713481Sgiacomo.travaglini@arm.com 135813481Sgiacomo.travaglini@arm.comIf you are designing an interface or concept, you can define a suite 135913481Sgiacomo.travaglini@arm.comof type-parameterized tests to verify properties that any valid 136013481Sgiacomo.travaglini@arm.comimplementation of the interface/concept should have. Then, the author 136113481Sgiacomo.travaglini@arm.comof each implementation can just instantiate the test suite with his 136213481Sgiacomo.travaglini@arm.comtype to verify that it conforms to the requirements, without having to 136313481Sgiacomo.travaglini@arm.comwrite similar tests repeatedly. Here's an example: 136413481Sgiacomo.travaglini@arm.com 136513481Sgiacomo.travaglini@arm.comFirst, define a fixture class template, as we did with typed tests: 136613481Sgiacomo.travaglini@arm.com 136713481Sgiacomo.travaglini@arm.com``` 136813481Sgiacomo.travaglini@arm.comtemplate <typename T> 136913481Sgiacomo.travaglini@arm.comclass FooTest : public ::testing::Test { 137013481Sgiacomo.travaglini@arm.com ... 137113481Sgiacomo.travaglini@arm.com}; 137213481Sgiacomo.travaglini@arm.com``` 137313481Sgiacomo.travaglini@arm.com 137413481Sgiacomo.travaglini@arm.comNext, declare that you will define a type-parameterized test case: 137513481Sgiacomo.travaglini@arm.com 137613481Sgiacomo.travaglini@arm.com``` 137713481Sgiacomo.travaglini@arm.comTYPED_TEST_CASE_P(FooTest); 137813481Sgiacomo.travaglini@arm.com``` 137913481Sgiacomo.travaglini@arm.com 138013481Sgiacomo.travaglini@arm.comThe `_P` suffix is for "parameterized" or "pattern", whichever you 138113481Sgiacomo.travaglini@arm.comprefer to think. 138213481Sgiacomo.travaglini@arm.com 138313481Sgiacomo.travaglini@arm.comThen, use `TYPED_TEST_P()` to define a type-parameterized test. You 138413481Sgiacomo.travaglini@arm.comcan repeat this as many times as you want: 138513481Sgiacomo.travaglini@arm.com 138613481Sgiacomo.travaglini@arm.com``` 138713481Sgiacomo.travaglini@arm.comTYPED_TEST_P(FooTest, DoesBlah) { 138813481Sgiacomo.travaglini@arm.com // Inside a test, refer to TypeParam to get the type parameter. 138913481Sgiacomo.travaglini@arm.com TypeParam n = 0; 139013481Sgiacomo.travaglini@arm.com ... 139113481Sgiacomo.travaglini@arm.com} 139213481Sgiacomo.travaglini@arm.com 139313481Sgiacomo.travaglini@arm.comTYPED_TEST_P(FooTest, HasPropertyA) { ... } 139413481Sgiacomo.travaglini@arm.com``` 139513481Sgiacomo.travaglini@arm.com 139613481Sgiacomo.travaglini@arm.comNow the tricky part: you need to register all test patterns using the 139713481Sgiacomo.travaglini@arm.com`REGISTER_TYPED_TEST_CASE_P` macro before you can instantiate them. 139813481Sgiacomo.travaglini@arm.comThe first argument of the macro is the test case name; the rest are 139913481Sgiacomo.travaglini@arm.comthe names of the tests in this test case: 140013481Sgiacomo.travaglini@arm.com 140113481Sgiacomo.travaglini@arm.com``` 140213481Sgiacomo.travaglini@arm.comREGISTER_TYPED_TEST_CASE_P(FooTest, 140313481Sgiacomo.travaglini@arm.com DoesBlah, HasPropertyA); 140413481Sgiacomo.travaglini@arm.com``` 140513481Sgiacomo.travaglini@arm.com 140613481Sgiacomo.travaglini@arm.comFinally, you are free to instantiate the pattern with the types you 140713481Sgiacomo.travaglini@arm.comwant. If you put the above code in a header file, you can `#include` 140813481Sgiacomo.travaglini@arm.comit in multiple C++ source files and instantiate it multiple times. 140913481Sgiacomo.travaglini@arm.com 141013481Sgiacomo.travaglini@arm.com``` 141113481Sgiacomo.travaglini@arm.comtypedef ::testing::Types<char, int, unsigned int> MyTypes; 141213481Sgiacomo.travaglini@arm.comINSTANTIATE_TYPED_TEST_CASE_P(My, FooTest, MyTypes); 141313481Sgiacomo.travaglini@arm.com``` 141413481Sgiacomo.travaglini@arm.com 141513481Sgiacomo.travaglini@arm.comTo distinguish different instances of the pattern, the first argument 141613481Sgiacomo.travaglini@arm.comto the `INSTANTIATE_TYPED_TEST_CASE_P` macro is a prefix that will be 141713481Sgiacomo.travaglini@arm.comadded to the actual test case name. Remember to pick unique prefixes 141813481Sgiacomo.travaglini@arm.comfor different instances. 141913481Sgiacomo.travaglini@arm.com 142013481Sgiacomo.travaglini@arm.comIn the special case where the type list contains only one type, you 142113481Sgiacomo.travaglini@arm.comcan write that type directly without `::testing::Types<...>`, like this: 142213481Sgiacomo.travaglini@arm.com 142313481Sgiacomo.travaglini@arm.com``` 142413481Sgiacomo.travaglini@arm.comINSTANTIATE_TYPED_TEST_CASE_P(My, FooTest, int); 142513481Sgiacomo.travaglini@arm.com``` 142613481Sgiacomo.travaglini@arm.com 142713481Sgiacomo.travaglini@arm.comYou can see `samples/sample6_unittest.cc` for a complete example. 142813481Sgiacomo.travaglini@arm.com 142913481Sgiacomo.travaglini@arm.com_Availability:_ Linux, Windows (requires MSVC 8.0 or above), Mac; 143013481Sgiacomo.travaglini@arm.comsince version 1.1.0. 143113481Sgiacomo.travaglini@arm.com 143213481Sgiacomo.travaglini@arm.com# Testing Private Code # 143313481Sgiacomo.travaglini@arm.com 143413481Sgiacomo.travaglini@arm.comIf you change your software's internal implementation, your tests should not 143513481Sgiacomo.travaglini@arm.combreak as long as the change is not observable by users. Therefore, per the 143613481Sgiacomo.travaglini@arm.com_black-box testing principle_, most of the time you should test your code 143713481Sgiacomo.travaglini@arm.comthrough its public interfaces. 143813481Sgiacomo.travaglini@arm.com 143913481Sgiacomo.travaglini@arm.comIf you still find yourself needing to test internal implementation code, 144013481Sgiacomo.travaglini@arm.comconsider if there's a better design that wouldn't require you to do so. If you 144113481Sgiacomo.travaglini@arm.comabsolutely have to test non-public interface code though, you can. There are 144213481Sgiacomo.travaglini@arm.comtwo cases to consider: 144313481Sgiacomo.travaglini@arm.com 144413481Sgiacomo.travaglini@arm.com * Static functions (_not_ the same as static member functions!) or unnamed namespaces, and 144513481Sgiacomo.travaglini@arm.com * Private or protected class members 144613481Sgiacomo.travaglini@arm.com 144713481Sgiacomo.travaglini@arm.com## Static Functions ## 144813481Sgiacomo.travaglini@arm.com 144913481Sgiacomo.travaglini@arm.comBoth static functions and definitions/declarations in an unnamed namespace are 145013481Sgiacomo.travaglini@arm.comonly visible within the same translation unit. To test them, you can `#include` 145113481Sgiacomo.travaglini@arm.comthe entire `.cc` file being tested in your `*_test.cc` file. (`#include`ing `.cc` 145213481Sgiacomo.travaglini@arm.comfiles is not a good way to reuse code - you should not do this in production 145313481Sgiacomo.travaglini@arm.comcode!) 145413481Sgiacomo.travaglini@arm.com 145513481Sgiacomo.travaglini@arm.comHowever, a better approach is to move the private code into the 145613481Sgiacomo.travaglini@arm.com`foo::internal` namespace, where `foo` is the namespace your project normally 145713481Sgiacomo.travaglini@arm.comuses, and put the private declarations in a `*-internal.h` file. Your 145813481Sgiacomo.travaglini@arm.comproduction `.cc` files and your tests are allowed to include this internal 145913481Sgiacomo.travaglini@arm.comheader, but your clients are not. This way, you can fully test your internal 146013481Sgiacomo.travaglini@arm.comimplementation without leaking it to your clients. 146113481Sgiacomo.travaglini@arm.com 146213481Sgiacomo.travaglini@arm.com## Private Class Members ## 146313481Sgiacomo.travaglini@arm.com 146413481Sgiacomo.travaglini@arm.comPrivate class members are only accessible from within the class or by friends. 146513481Sgiacomo.travaglini@arm.comTo access a class' private members, you can declare your test fixture as a 146613481Sgiacomo.travaglini@arm.comfriend to the class and define accessors in your fixture. Tests using the 146713481Sgiacomo.travaglini@arm.comfixture can then access the private members of your production class via the 146813481Sgiacomo.travaglini@arm.comaccessors in the fixture. Note that even though your fixture is a friend to 146913481Sgiacomo.travaglini@arm.comyour production class, your tests are not automatically friends to it, as they 147013481Sgiacomo.travaglini@arm.comare technically defined in sub-classes of the fixture. 147113481Sgiacomo.travaglini@arm.com 147213481Sgiacomo.travaglini@arm.comAnother way to test private members is to refactor them into an implementation 147313481Sgiacomo.travaglini@arm.comclass, which is then declared in a `*-internal.h` file. Your clients aren't 147413481Sgiacomo.travaglini@arm.comallowed to include this header but your tests can. Such is called the Pimpl 147513481Sgiacomo.travaglini@arm.com(Private Implementation) idiom. 147613481Sgiacomo.travaglini@arm.com 147713481Sgiacomo.travaglini@arm.comOr, you can declare an individual test as a friend of your class by adding this 147813481Sgiacomo.travaglini@arm.comline in the class body: 147913481Sgiacomo.travaglini@arm.com 148013481Sgiacomo.travaglini@arm.com``` 148113481Sgiacomo.travaglini@arm.comFRIEND_TEST(TestCaseName, TestName); 148213481Sgiacomo.travaglini@arm.com``` 148313481Sgiacomo.travaglini@arm.com 148413481Sgiacomo.travaglini@arm.comFor example, 148513481Sgiacomo.travaglini@arm.com``` 148613481Sgiacomo.travaglini@arm.com// foo.h 148713481Sgiacomo.travaglini@arm.com#include "gtest/gtest_prod.h" 148813481Sgiacomo.travaglini@arm.com 148913481Sgiacomo.travaglini@arm.com// Defines FRIEND_TEST. 149013481Sgiacomo.travaglini@arm.comclass Foo { 149113481Sgiacomo.travaglini@arm.com ... 149213481Sgiacomo.travaglini@arm.com private: 149313481Sgiacomo.travaglini@arm.com FRIEND_TEST(FooTest, BarReturnsZeroOnNull); 149413481Sgiacomo.travaglini@arm.com int Bar(void* x); 149513481Sgiacomo.travaglini@arm.com}; 149613481Sgiacomo.travaglini@arm.com 149713481Sgiacomo.travaglini@arm.com// foo_test.cc 149813481Sgiacomo.travaglini@arm.com... 149913481Sgiacomo.travaglini@arm.comTEST(FooTest, BarReturnsZeroOnNull) { 150013481Sgiacomo.travaglini@arm.com Foo foo; 150113481Sgiacomo.travaglini@arm.com EXPECT_EQ(0, foo.Bar(NULL)); 150213481Sgiacomo.travaglini@arm.com // Uses Foo's private member Bar(). 150313481Sgiacomo.travaglini@arm.com} 150413481Sgiacomo.travaglini@arm.com``` 150513481Sgiacomo.travaglini@arm.com 150613481Sgiacomo.travaglini@arm.comPay special attention when your class is defined in a namespace, as you should 150713481Sgiacomo.travaglini@arm.comdefine your test fixtures and tests in the same namespace if you want them to 150813481Sgiacomo.travaglini@arm.combe friends of your class. For example, if the code to be tested looks like: 150913481Sgiacomo.travaglini@arm.com 151013481Sgiacomo.travaglini@arm.com``` 151113481Sgiacomo.travaglini@arm.comnamespace my_namespace { 151213481Sgiacomo.travaglini@arm.com 151313481Sgiacomo.travaglini@arm.comclass Foo { 151413481Sgiacomo.travaglini@arm.com friend class FooTest; 151513481Sgiacomo.travaglini@arm.com FRIEND_TEST(FooTest, Bar); 151613481Sgiacomo.travaglini@arm.com FRIEND_TEST(FooTest, Baz); 151713481Sgiacomo.travaglini@arm.com ... 151813481Sgiacomo.travaglini@arm.com definition of the class Foo 151913481Sgiacomo.travaglini@arm.com ... 152013481Sgiacomo.travaglini@arm.com}; 152113481Sgiacomo.travaglini@arm.com 152213481Sgiacomo.travaglini@arm.com} // namespace my_namespace 152313481Sgiacomo.travaglini@arm.com``` 152413481Sgiacomo.travaglini@arm.com 152513481Sgiacomo.travaglini@arm.comYour test code should be something like: 152613481Sgiacomo.travaglini@arm.com 152713481Sgiacomo.travaglini@arm.com``` 152813481Sgiacomo.travaglini@arm.comnamespace my_namespace { 152913481Sgiacomo.travaglini@arm.comclass FooTest : public ::testing::Test { 153013481Sgiacomo.travaglini@arm.com protected: 153113481Sgiacomo.travaglini@arm.com ... 153213481Sgiacomo.travaglini@arm.com}; 153313481Sgiacomo.travaglini@arm.com 153413481Sgiacomo.travaglini@arm.comTEST_F(FooTest, Bar) { ... } 153513481Sgiacomo.travaglini@arm.comTEST_F(FooTest, Baz) { ... } 153613481Sgiacomo.travaglini@arm.com 153713481Sgiacomo.travaglini@arm.com} // namespace my_namespace 153813481Sgiacomo.travaglini@arm.com``` 153913481Sgiacomo.travaglini@arm.com 154013481Sgiacomo.travaglini@arm.com# Catching Failures # 154113481Sgiacomo.travaglini@arm.com 154213481Sgiacomo.travaglini@arm.comIf you are building a testing utility on top of Google Test, you'll 154313481Sgiacomo.travaglini@arm.comwant to test your utility. What framework would you use to test it? 154413481Sgiacomo.travaglini@arm.comGoogle Test, of course. 154513481Sgiacomo.travaglini@arm.com 154613481Sgiacomo.travaglini@arm.comThe challenge is to verify that your testing utility reports failures 154713481Sgiacomo.travaglini@arm.comcorrectly. In frameworks that report a failure by throwing an 154813481Sgiacomo.travaglini@arm.comexception, you could catch the exception and assert on it. But Google 154913481Sgiacomo.travaglini@arm.comTest doesn't use exceptions, so how do we test that a piece of code 155013481Sgiacomo.travaglini@arm.comgenerates an expected failure? 155113481Sgiacomo.travaglini@arm.com 155213481Sgiacomo.travaglini@arm.com`"gtest/gtest-spi.h"` contains some constructs to do this. After 155313481Sgiacomo.travaglini@arm.com`#include`ing this header, you can use 155413481Sgiacomo.travaglini@arm.com 155513481Sgiacomo.travaglini@arm.com| `EXPECT_FATAL_FAILURE(`_statement, substring_`);` | 155613481Sgiacomo.travaglini@arm.com|:--------------------------------------------------| 155713481Sgiacomo.travaglini@arm.com 155813481Sgiacomo.travaglini@arm.comto assert that _statement_ generates a fatal (e.g. `ASSERT_*`) failure 155913481Sgiacomo.travaglini@arm.comwhose message contains the given _substring_, or use 156013481Sgiacomo.travaglini@arm.com 156113481Sgiacomo.travaglini@arm.com| `EXPECT_NONFATAL_FAILURE(`_statement, substring_`);` | 156213481Sgiacomo.travaglini@arm.com|:-----------------------------------------------------| 156313481Sgiacomo.travaglini@arm.com 156413481Sgiacomo.travaglini@arm.comif you are expecting a non-fatal (e.g. `EXPECT_*`) failure. 156513481Sgiacomo.travaglini@arm.com 156613481Sgiacomo.travaglini@arm.comFor technical reasons, there are some caveats: 156713481Sgiacomo.travaglini@arm.com 156813481Sgiacomo.travaglini@arm.com 1. You cannot stream a failure message to either macro. 156913481Sgiacomo.travaglini@arm.com 1. _statement_ in `EXPECT_FATAL_FAILURE()` cannot reference local non-static variables or non-static members of `this` object. 157013481Sgiacomo.travaglini@arm.com 1. _statement_ in `EXPECT_FATAL_FAILURE()` cannot return a value. 157113481Sgiacomo.travaglini@arm.com 157213481Sgiacomo.travaglini@arm.com_Note:_ Google Test is designed with threads in mind. Once the 157313481Sgiacomo.travaglini@arm.comsynchronization primitives in `"gtest/internal/gtest-port.h"` have 157413481Sgiacomo.travaglini@arm.combeen implemented, Google Test will become thread-safe, meaning that 157513481Sgiacomo.travaglini@arm.comyou can then use assertions in multiple threads concurrently. Before 157613481Sgiacomo.travaglini@arm.com 157713481Sgiacomo.travaglini@arm.comthat, however, Google Test only supports single-threaded usage. Once 157813481Sgiacomo.travaglini@arm.comthread-safe, `EXPECT_FATAL_FAILURE()` and `EXPECT_NONFATAL_FAILURE()` 157913481Sgiacomo.travaglini@arm.comwill capture failures in the current thread only. If _statement_ 158013481Sgiacomo.travaglini@arm.comcreates new threads, failures in these threads will be ignored. If 158113481Sgiacomo.travaglini@arm.comyou want to capture failures from all threads instead, you should use 158213481Sgiacomo.travaglini@arm.comthe following macros: 158313481Sgiacomo.travaglini@arm.com 158413481Sgiacomo.travaglini@arm.com| `EXPECT_FATAL_FAILURE_ON_ALL_THREADS(`_statement, substring_`);` | 158513481Sgiacomo.travaglini@arm.com|:-----------------------------------------------------------------| 158613481Sgiacomo.travaglini@arm.com| `EXPECT_NONFATAL_FAILURE_ON_ALL_THREADS(`_statement, substring_`);` | 158713481Sgiacomo.travaglini@arm.com 158813481Sgiacomo.travaglini@arm.com# Getting the Current Test's Name # 158913481Sgiacomo.travaglini@arm.com 159013481Sgiacomo.travaglini@arm.comSometimes a function may need to know the name of the currently running test. 159113481Sgiacomo.travaglini@arm.comFor example, you may be using the `SetUp()` method of your test fixture to set 159213481Sgiacomo.travaglini@arm.comthe golden file name based on which test is running. The `::testing::TestInfo` 159313481Sgiacomo.travaglini@arm.comclass has this information: 159413481Sgiacomo.travaglini@arm.com 159513481Sgiacomo.travaglini@arm.com``` 159613481Sgiacomo.travaglini@arm.comnamespace testing { 159713481Sgiacomo.travaglini@arm.com 159813481Sgiacomo.travaglini@arm.comclass TestInfo { 159913481Sgiacomo.travaglini@arm.com public: 160013481Sgiacomo.travaglini@arm.com // Returns the test case name and the test name, respectively. 160113481Sgiacomo.travaglini@arm.com // 160213481Sgiacomo.travaglini@arm.com // Do NOT delete or free the return value - it's managed by the 160313481Sgiacomo.travaglini@arm.com // TestInfo class. 160413481Sgiacomo.travaglini@arm.com const char* test_case_name() const; 160513481Sgiacomo.travaglini@arm.com const char* name() const; 160613481Sgiacomo.travaglini@arm.com}; 160713481Sgiacomo.travaglini@arm.com 160813481Sgiacomo.travaglini@arm.com} // namespace testing 160913481Sgiacomo.travaglini@arm.com``` 161013481Sgiacomo.travaglini@arm.com 161113481Sgiacomo.travaglini@arm.com 161213481Sgiacomo.travaglini@arm.com> To obtain a `TestInfo` object for the currently running test, call 161313481Sgiacomo.travaglini@arm.com`current_test_info()` on the `UnitTest` singleton object: 161413481Sgiacomo.travaglini@arm.com 161513481Sgiacomo.travaglini@arm.com``` 161613481Sgiacomo.travaglini@arm.com// Gets information about the currently running test. 161713481Sgiacomo.travaglini@arm.com// Do NOT delete the returned object - it's managed by the UnitTest class. 161813481Sgiacomo.travaglini@arm.comconst ::testing::TestInfo* const test_info = 161913481Sgiacomo.travaglini@arm.com ::testing::UnitTest::GetInstance()->current_test_info(); 162013481Sgiacomo.travaglini@arm.comprintf("We are in test %s of test case %s.\n", 162113481Sgiacomo.travaglini@arm.com test_info->name(), test_info->test_case_name()); 162213481Sgiacomo.travaglini@arm.com``` 162313481Sgiacomo.travaglini@arm.com 162413481Sgiacomo.travaglini@arm.com`current_test_info()` returns a null pointer if no test is running. In 162513481Sgiacomo.travaglini@arm.comparticular, you cannot find the test case name in `TestCaseSetUp()`, 162613481Sgiacomo.travaglini@arm.com`TestCaseTearDown()` (where you know the test case name implicitly), or 162713481Sgiacomo.travaglini@arm.comfunctions called from them. 162813481Sgiacomo.travaglini@arm.com 162913481Sgiacomo.travaglini@arm.com_Availability:_ Linux, Windows, Mac. 163013481Sgiacomo.travaglini@arm.com 163113481Sgiacomo.travaglini@arm.com# Extending Google Test by Handling Test Events # 163213481Sgiacomo.travaglini@arm.com 163313481Sgiacomo.travaglini@arm.comGoogle Test provides an <b>event listener API</b> to let you receive 163413481Sgiacomo.travaglini@arm.comnotifications about the progress of a test program and test 163513481Sgiacomo.travaglini@arm.comfailures. The events you can listen to include the start and end of 163613481Sgiacomo.travaglini@arm.comthe test program, a test case, or a test method, among others. You may 163713481Sgiacomo.travaglini@arm.comuse this API to augment or replace the standard console output, 163813481Sgiacomo.travaglini@arm.comreplace the XML output, or provide a completely different form of 163913481Sgiacomo.travaglini@arm.comoutput, such as a GUI or a database. You can also use test events as 164013481Sgiacomo.travaglini@arm.comcheckpoints to implement a resource leak checker, for example. 164113481Sgiacomo.travaglini@arm.com 164213481Sgiacomo.travaglini@arm.com_Availability:_ Linux, Windows, Mac; since v1.4.0. 164313481Sgiacomo.travaglini@arm.com 164413481Sgiacomo.travaglini@arm.com## Defining Event Listeners ## 164513481Sgiacomo.travaglini@arm.com 164613481Sgiacomo.travaglini@arm.comTo define a event listener, you subclass either 164713481Sgiacomo.travaglini@arm.com[testing::TestEventListener](../include/gtest/gtest.h#L855) 164813481Sgiacomo.travaglini@arm.comor [testing::EmptyTestEventListener](../include/gtest/gtest.h#L905). 164913481Sgiacomo.travaglini@arm.comThe former is an (abstract) interface, where <i>each pure virtual method<br> 165013481Sgiacomo.travaglini@arm.comcan be overridden to handle a test event</i> (For example, when a test 165113481Sgiacomo.travaglini@arm.comstarts, the `OnTestStart()` method will be called.). The latter provides 165213481Sgiacomo.travaglini@arm.coman empty implementation of all methods in the interface, such that a 165313481Sgiacomo.travaglini@arm.comsubclass only needs to override the methods it cares about. 165413481Sgiacomo.travaglini@arm.com 165513481Sgiacomo.travaglini@arm.comWhen an event is fired, its context is passed to the handler function 165613481Sgiacomo.travaglini@arm.comas an argument. The following argument types are used: 165713481Sgiacomo.travaglini@arm.com * [UnitTest](../include/gtest/gtest.h#L1007) reflects the state of the entire test program, 165813481Sgiacomo.travaglini@arm.com * [TestCase](../include/gtest/gtest.h#L689) has information about a test case, which can contain one or more tests, 165913481Sgiacomo.travaglini@arm.com * [TestInfo](../include/gtest/gtest.h#L599) contains the state of a test, and 166013481Sgiacomo.travaglini@arm.com * [TestPartResult](../include/gtest/gtest-test-part.h#L42) represents the result of a test assertion. 166113481Sgiacomo.travaglini@arm.com 166213481Sgiacomo.travaglini@arm.comAn event handler function can examine the argument it receives to find 166313481Sgiacomo.travaglini@arm.comout interesting information about the event and the test program's 166413481Sgiacomo.travaglini@arm.comstate. Here's an example: 166513481Sgiacomo.travaglini@arm.com 166613481Sgiacomo.travaglini@arm.com``` 166713481Sgiacomo.travaglini@arm.com class MinimalistPrinter : public ::testing::EmptyTestEventListener { 166813481Sgiacomo.travaglini@arm.com // Called before a test starts. 166913481Sgiacomo.travaglini@arm.com virtual void OnTestStart(const ::testing::TestInfo& test_info) { 167013481Sgiacomo.travaglini@arm.com printf("*** Test %s.%s starting.\n", 167113481Sgiacomo.travaglini@arm.com test_info.test_case_name(), test_info.name()); 167213481Sgiacomo.travaglini@arm.com } 167313481Sgiacomo.travaglini@arm.com 167413481Sgiacomo.travaglini@arm.com // Called after a failed assertion or a SUCCEED() invocation. 167513481Sgiacomo.travaglini@arm.com virtual void OnTestPartResult( 167613481Sgiacomo.travaglini@arm.com const ::testing::TestPartResult& test_part_result) { 167713481Sgiacomo.travaglini@arm.com printf("%s in %s:%d\n%s\n", 167813481Sgiacomo.travaglini@arm.com test_part_result.failed() ? "*** Failure" : "Success", 167913481Sgiacomo.travaglini@arm.com test_part_result.file_name(), 168013481Sgiacomo.travaglini@arm.com test_part_result.line_number(), 168113481Sgiacomo.travaglini@arm.com test_part_result.summary()); 168213481Sgiacomo.travaglini@arm.com } 168313481Sgiacomo.travaglini@arm.com 168413481Sgiacomo.travaglini@arm.com // Called after a test ends. 168513481Sgiacomo.travaglini@arm.com virtual void OnTestEnd(const ::testing::TestInfo& test_info) { 168613481Sgiacomo.travaglini@arm.com printf("*** Test %s.%s ending.\n", 168713481Sgiacomo.travaglini@arm.com test_info.test_case_name(), test_info.name()); 168813481Sgiacomo.travaglini@arm.com } 168913481Sgiacomo.travaglini@arm.com }; 169013481Sgiacomo.travaglini@arm.com``` 169113481Sgiacomo.travaglini@arm.com 169213481Sgiacomo.travaglini@arm.com## Using Event Listeners ## 169313481Sgiacomo.travaglini@arm.com 169413481Sgiacomo.travaglini@arm.comTo use the event listener you have defined, add an instance of it to 169513481Sgiacomo.travaglini@arm.comthe Google Test event listener list (represented by class 169613481Sgiacomo.travaglini@arm.com[TestEventListeners](../include/gtest/gtest.h#L929) 169713481Sgiacomo.travaglini@arm.com- note the "s" at the end of the name) in your 169813481Sgiacomo.travaglini@arm.com`main()` function, before calling `RUN_ALL_TESTS()`: 169913481Sgiacomo.travaglini@arm.com``` 170013481Sgiacomo.travaglini@arm.comint main(int argc, char** argv) { 170113481Sgiacomo.travaglini@arm.com ::testing::InitGoogleTest(&argc, argv); 170213481Sgiacomo.travaglini@arm.com // Gets hold of the event listener list. 170313481Sgiacomo.travaglini@arm.com ::testing::TestEventListeners& listeners = 170413481Sgiacomo.travaglini@arm.com ::testing::UnitTest::GetInstance()->listeners(); 170513481Sgiacomo.travaglini@arm.com // Adds a listener to the end. Google Test takes the ownership. 170613481Sgiacomo.travaglini@arm.com listeners.Append(new MinimalistPrinter); 170713481Sgiacomo.travaglini@arm.com return RUN_ALL_TESTS(); 170813481Sgiacomo.travaglini@arm.com} 170913481Sgiacomo.travaglini@arm.com``` 171013481Sgiacomo.travaglini@arm.com 171113481Sgiacomo.travaglini@arm.comThere's only one problem: the default test result printer is still in 171213481Sgiacomo.travaglini@arm.comeffect, so its output will mingle with the output from your minimalist 171313481Sgiacomo.travaglini@arm.comprinter. To suppress the default printer, just release it from the 171413481Sgiacomo.travaglini@arm.comevent listener list and delete it. You can do so by adding one line: 171513481Sgiacomo.travaglini@arm.com``` 171613481Sgiacomo.travaglini@arm.com ... 171713481Sgiacomo.travaglini@arm.com delete listeners.Release(listeners.default_result_printer()); 171813481Sgiacomo.travaglini@arm.com listeners.Append(new MinimalistPrinter); 171913481Sgiacomo.travaglini@arm.com return RUN_ALL_TESTS(); 172013481Sgiacomo.travaglini@arm.com``` 172113481Sgiacomo.travaglini@arm.com 172213481Sgiacomo.travaglini@arm.comNow, sit back and enjoy a completely different output from your 172313481Sgiacomo.travaglini@arm.comtests. For more details, you can read this 172413481Sgiacomo.travaglini@arm.com[sample](../samples/sample9_unittest.cc). 172513481Sgiacomo.travaglini@arm.com 172613481Sgiacomo.travaglini@arm.comYou may append more than one listener to the list. When an `On*Start()` 172713481Sgiacomo.travaglini@arm.comor `OnTestPartResult()` event is fired, the listeners will receive it in 172813481Sgiacomo.travaglini@arm.comthe order they appear in the list (since new listeners are added to 172913481Sgiacomo.travaglini@arm.comthe end of the list, the default text printer and the default XML 173013481Sgiacomo.travaglini@arm.comgenerator will receive the event first). An `On*End()` event will be 173113481Sgiacomo.travaglini@arm.comreceived by the listeners in the _reverse_ order. This allows output by 173213481Sgiacomo.travaglini@arm.comlisteners added later to be framed by output from listeners added 173313481Sgiacomo.travaglini@arm.comearlier. 173413481Sgiacomo.travaglini@arm.com 173513481Sgiacomo.travaglini@arm.com## Generating Failures in Listeners ## 173613481Sgiacomo.travaglini@arm.com 173713481Sgiacomo.travaglini@arm.comYou may use failure-raising macros (`EXPECT_*()`, `ASSERT_*()`, 173813481Sgiacomo.travaglini@arm.com`FAIL()`, etc) when processing an event. There are some restrictions: 173913481Sgiacomo.travaglini@arm.com 174013481Sgiacomo.travaglini@arm.com 1. You cannot generate any failure in `OnTestPartResult()` (otherwise it will cause `OnTestPartResult()` to be called recursively). 174113481Sgiacomo.travaglini@arm.com 1. A listener that handles `OnTestPartResult()` is not allowed to generate any failure. 174213481Sgiacomo.travaglini@arm.com 174313481Sgiacomo.travaglini@arm.comWhen you add listeners to the listener list, you should put listeners 174413481Sgiacomo.travaglini@arm.comthat handle `OnTestPartResult()` _before_ listeners that can generate 174513481Sgiacomo.travaglini@arm.comfailures. This ensures that failures generated by the latter are 174613481Sgiacomo.travaglini@arm.comattributed to the right test by the former. 174713481Sgiacomo.travaglini@arm.com 174813481Sgiacomo.travaglini@arm.comWe have a sample of failure-raising listener 174913481Sgiacomo.travaglini@arm.com[here](../samples/sample10_unittest.cc). 175013481Sgiacomo.travaglini@arm.com 175113481Sgiacomo.travaglini@arm.com# Running Test Programs: Advanced Options # 175213481Sgiacomo.travaglini@arm.com 175313481Sgiacomo.travaglini@arm.comGoogle Test test programs are ordinary executables. Once built, you can run 175413481Sgiacomo.travaglini@arm.comthem directly and affect their behavior via the following environment variables 175513481Sgiacomo.travaglini@arm.comand/or command line flags. For the flags to work, your programs must call 175613481Sgiacomo.travaglini@arm.com`::testing::InitGoogleTest()` before calling `RUN_ALL_TESTS()`. 175713481Sgiacomo.travaglini@arm.com 175813481Sgiacomo.travaglini@arm.comTo see a list of supported flags and their usage, please run your test 175913481Sgiacomo.travaglini@arm.comprogram with the `--help` flag. You can also use `-h`, `-?`, or `/?` 176013481Sgiacomo.travaglini@arm.comfor short. This feature is added in version 1.3.0. 176113481Sgiacomo.travaglini@arm.com 176213481Sgiacomo.travaglini@arm.comIf an option is specified both by an environment variable and by a 176313481Sgiacomo.travaglini@arm.comflag, the latter takes precedence. Most of the options can also be 176413481Sgiacomo.travaglini@arm.comset/read in code: to access the value of command line flag 176513481Sgiacomo.travaglini@arm.com`--gtest_foo`, write `::testing::GTEST_FLAG(foo)`. A common pattern is 176613481Sgiacomo.travaglini@arm.comto set the value of a flag before calling `::testing::InitGoogleTest()` 176713481Sgiacomo.travaglini@arm.comto change the default value of the flag: 176813481Sgiacomo.travaglini@arm.com``` 176913481Sgiacomo.travaglini@arm.comint main(int argc, char** argv) { 177013481Sgiacomo.travaglini@arm.com // Disables elapsed time by default. 177113481Sgiacomo.travaglini@arm.com ::testing::GTEST_FLAG(print_time) = false; 177213481Sgiacomo.travaglini@arm.com 177313481Sgiacomo.travaglini@arm.com // This allows the user to override the flag on the command line. 177413481Sgiacomo.travaglini@arm.com ::testing::InitGoogleTest(&argc, argv); 177513481Sgiacomo.travaglini@arm.com 177613481Sgiacomo.travaglini@arm.com return RUN_ALL_TESTS(); 177713481Sgiacomo.travaglini@arm.com} 177813481Sgiacomo.travaglini@arm.com``` 177913481Sgiacomo.travaglini@arm.com 178013481Sgiacomo.travaglini@arm.com## Selecting Tests ## 178113481Sgiacomo.travaglini@arm.com 178213481Sgiacomo.travaglini@arm.comThis section shows various options for choosing which tests to run. 178313481Sgiacomo.travaglini@arm.com 178413481Sgiacomo.travaglini@arm.com### Listing Test Names ### 178513481Sgiacomo.travaglini@arm.com 178613481Sgiacomo.travaglini@arm.comSometimes it is necessary to list the available tests in a program before 178713481Sgiacomo.travaglini@arm.comrunning them so that a filter may be applied if needed. Including the flag 178813481Sgiacomo.travaglini@arm.com`--gtest_list_tests` overrides all other flags and lists tests in the following 178913481Sgiacomo.travaglini@arm.comformat: 179013481Sgiacomo.travaglini@arm.com``` 179113481Sgiacomo.travaglini@arm.comTestCase1. 179213481Sgiacomo.travaglini@arm.com TestName1 179313481Sgiacomo.travaglini@arm.com TestName2 179413481Sgiacomo.travaglini@arm.comTestCase2. 179513481Sgiacomo.travaglini@arm.com TestName 179613481Sgiacomo.travaglini@arm.com``` 179713481Sgiacomo.travaglini@arm.com 179813481Sgiacomo.travaglini@arm.comNone of the tests listed are actually run if the flag is provided. There is no 179913481Sgiacomo.travaglini@arm.comcorresponding environment variable for this flag. 180013481Sgiacomo.travaglini@arm.com 180113481Sgiacomo.travaglini@arm.com_Availability:_ Linux, Windows, Mac. 180213481Sgiacomo.travaglini@arm.com 180313481Sgiacomo.travaglini@arm.com### Running a Subset of the Tests ### 180413481Sgiacomo.travaglini@arm.com 180513481Sgiacomo.travaglini@arm.comBy default, a Google Test program runs all tests the user has defined. 180613481Sgiacomo.travaglini@arm.comSometimes, you want to run only a subset of the tests (e.g. for debugging or 180713481Sgiacomo.travaglini@arm.comquickly verifying a change). If you set the `GTEST_FILTER` environment variable 180813481Sgiacomo.travaglini@arm.comor the `--gtest_filter` flag to a filter string, Google Test will only run the 180913481Sgiacomo.travaglini@arm.comtests whose full names (in the form of `TestCaseName.TestName`) match the 181013481Sgiacomo.travaglini@arm.comfilter. 181113481Sgiacomo.travaglini@arm.com 181213481Sgiacomo.travaglini@arm.comThe format of a filter is a '`:`'-separated list of wildcard patterns (called 181313481Sgiacomo.travaglini@arm.comthe positive patterns) optionally followed by a '`-`' and another 181413481Sgiacomo.travaglini@arm.com'`:`'-separated pattern list (called the negative patterns). A test matches the 181513481Sgiacomo.travaglini@arm.comfilter if and only if it matches any of the positive patterns but does not 181613481Sgiacomo.travaglini@arm.commatch any of the negative patterns. 181713481Sgiacomo.travaglini@arm.com 181813481Sgiacomo.travaglini@arm.comA pattern may contain `'*'` (matches any string) or `'?'` (matches any single 181913481Sgiacomo.travaglini@arm.comcharacter). For convenience, the filter `'*-NegativePatterns'` can be also 182013481Sgiacomo.travaglini@arm.comwritten as `'-NegativePatterns'`. 182113481Sgiacomo.travaglini@arm.com 182213481Sgiacomo.travaglini@arm.comFor example: 182313481Sgiacomo.travaglini@arm.com 182413481Sgiacomo.travaglini@arm.com * `./foo_test` Has no flag, and thus runs all its tests. 182513481Sgiacomo.travaglini@arm.com * `./foo_test --gtest_filter=*` Also runs everything, due to the single match-everything `*` value. 182613481Sgiacomo.travaglini@arm.com * `./foo_test --gtest_filter=FooTest.*` Runs everything in test case `FooTest`. 182713481Sgiacomo.travaglini@arm.com * `./foo_test --gtest_filter=*Null*:*Constructor*` Runs any test whose full name contains either `"Null"` or `"Constructor"`. 182813481Sgiacomo.travaglini@arm.com * `./foo_test --gtest_filter=-*DeathTest.*` Runs all non-death tests. 182913481Sgiacomo.travaglini@arm.com * `./foo_test --gtest_filter=FooTest.*-FooTest.Bar` Runs everything in test case `FooTest` except `FooTest.Bar`. 183013481Sgiacomo.travaglini@arm.com 183113481Sgiacomo.travaglini@arm.com_Availability:_ Linux, Windows, Mac. 183213481Sgiacomo.travaglini@arm.com 183313481Sgiacomo.travaglini@arm.com### Temporarily Disabling Tests ### 183413481Sgiacomo.travaglini@arm.com 183513481Sgiacomo.travaglini@arm.comIf you have a broken test that you cannot fix right away, you can add the 183613481Sgiacomo.travaglini@arm.com`DISABLED_` prefix to its name. This will exclude it from execution. This is 183713481Sgiacomo.travaglini@arm.combetter than commenting out the code or using `#if 0`, as disabled tests are 183813481Sgiacomo.travaglini@arm.comstill compiled (and thus won't rot). 183913481Sgiacomo.travaglini@arm.com 184013481Sgiacomo.travaglini@arm.comIf you need to disable all tests in a test case, you can either add `DISABLED_` 184113481Sgiacomo.travaglini@arm.comto the front of the name of each test, or alternatively add it to the front of 184213481Sgiacomo.travaglini@arm.comthe test case name. 184313481Sgiacomo.travaglini@arm.com 184413481Sgiacomo.travaglini@arm.comFor example, the following tests won't be run by Google Test, even though they 184513481Sgiacomo.travaglini@arm.comwill still be compiled: 184613481Sgiacomo.travaglini@arm.com 184713481Sgiacomo.travaglini@arm.com``` 184813481Sgiacomo.travaglini@arm.com// Tests that Foo does Abc. 184913481Sgiacomo.travaglini@arm.comTEST(FooTest, DISABLED_DoesAbc) { ... } 185013481Sgiacomo.travaglini@arm.com 185113481Sgiacomo.travaglini@arm.comclass DISABLED_BarTest : public ::testing::Test { ... }; 185213481Sgiacomo.travaglini@arm.com 185313481Sgiacomo.travaglini@arm.com// Tests that Bar does Xyz. 185413481Sgiacomo.travaglini@arm.comTEST_F(DISABLED_BarTest, DoesXyz) { ... } 185513481Sgiacomo.travaglini@arm.com``` 185613481Sgiacomo.travaglini@arm.com 185713481Sgiacomo.travaglini@arm.com_Note:_ This feature should only be used for temporary pain-relief. You still 185813481Sgiacomo.travaglini@arm.comhave to fix the disabled tests at a later date. As a reminder, Google Test will 185913481Sgiacomo.travaglini@arm.comprint a banner warning you if a test program contains any disabled tests. 186013481Sgiacomo.travaglini@arm.com 186113481Sgiacomo.travaglini@arm.com_Tip:_ You can easily count the number of disabled tests you have 186213481Sgiacomo.travaglini@arm.comusing `grep`. This number can be used as a metric for improving your 186313481Sgiacomo.travaglini@arm.comtest quality. 186413481Sgiacomo.travaglini@arm.com 186513481Sgiacomo.travaglini@arm.com_Availability:_ Linux, Windows, Mac. 186613481Sgiacomo.travaglini@arm.com 186713481Sgiacomo.travaglini@arm.com### Temporarily Enabling Disabled Tests ### 186813481Sgiacomo.travaglini@arm.com 186913481Sgiacomo.travaglini@arm.comTo include [disabled tests](#temporarily-disabling-tests) in test 187013481Sgiacomo.travaglini@arm.comexecution, just invoke the test program with the 187113481Sgiacomo.travaglini@arm.com`--gtest_also_run_disabled_tests` flag or set the 187213481Sgiacomo.travaglini@arm.com`GTEST_ALSO_RUN_DISABLED_TESTS` environment variable to a value other 187313481Sgiacomo.travaglini@arm.comthan `0`. You can combine this with the 187413481Sgiacomo.travaglini@arm.com[--gtest\_filter](#running-a-subset-of-the-tests) flag to further select 187513481Sgiacomo.travaglini@arm.comwhich disabled tests to run. 187613481Sgiacomo.travaglini@arm.com 187713481Sgiacomo.travaglini@arm.com_Availability:_ Linux, Windows, Mac; since version 1.3.0. 187813481Sgiacomo.travaglini@arm.com 187913481Sgiacomo.travaglini@arm.com## Repeating the Tests ## 188013481Sgiacomo.travaglini@arm.com 188113481Sgiacomo.travaglini@arm.comOnce in a while you'll run into a test whose result is hit-or-miss. Perhaps it 188213481Sgiacomo.travaglini@arm.comwill fail only 1% of the time, making it rather hard to reproduce the bug under 188313481Sgiacomo.travaglini@arm.coma debugger. This can be a major source of frustration. 188413481Sgiacomo.travaglini@arm.com 188513481Sgiacomo.travaglini@arm.comThe `--gtest_repeat` flag allows you to repeat all (or selected) test methods 188613481Sgiacomo.travaglini@arm.comin a program many times. Hopefully, a flaky test will eventually fail and give 188713481Sgiacomo.travaglini@arm.comyou a chance to debug. Here's how to use it: 188813481Sgiacomo.travaglini@arm.com 188913481Sgiacomo.travaglini@arm.com| `$ foo_test --gtest_repeat=1000` | Repeat foo\_test 1000 times and don't stop at failures. | 189013481Sgiacomo.travaglini@arm.com|:---------------------------------|:--------------------------------------------------------| 189113481Sgiacomo.travaglini@arm.com| `$ foo_test --gtest_repeat=-1` | A negative count means repeating forever. | 189213481Sgiacomo.travaglini@arm.com| `$ foo_test --gtest_repeat=1000 --gtest_break_on_failure` | Repeat foo\_test 1000 times, stopping at the first failure. This is especially useful when running under a debugger: when the testfails, it will drop into the debugger and you can then inspect variables and stacks. | 189313481Sgiacomo.travaglini@arm.com| `$ foo_test --gtest_repeat=1000 --gtest_filter=FooBar` | Repeat the tests whose name matches the filter 1000 times. | 189413481Sgiacomo.travaglini@arm.com 189513481Sgiacomo.travaglini@arm.comIf your test program contains global set-up/tear-down code registered 189613481Sgiacomo.travaglini@arm.comusing `AddGlobalTestEnvironment()`, it will be repeated in each 189713481Sgiacomo.travaglini@arm.comiteration as well, as the flakiness may be in it. You can also specify 189813481Sgiacomo.travaglini@arm.comthe repeat count by setting the `GTEST_REPEAT` environment variable. 189913481Sgiacomo.travaglini@arm.com 190013481Sgiacomo.travaglini@arm.com_Availability:_ Linux, Windows, Mac. 190113481Sgiacomo.travaglini@arm.com 190213481Sgiacomo.travaglini@arm.com## Shuffling the Tests ## 190313481Sgiacomo.travaglini@arm.com 190413481Sgiacomo.travaglini@arm.comYou can specify the `--gtest_shuffle` flag (or set the `GTEST_SHUFFLE` 190513481Sgiacomo.travaglini@arm.comenvironment variable to `1`) to run the tests in a program in a random 190613481Sgiacomo.travaglini@arm.comorder. This helps to reveal bad dependencies between tests. 190713481Sgiacomo.travaglini@arm.com 190813481Sgiacomo.travaglini@arm.comBy default, Google Test uses a random seed calculated from the current 190913481Sgiacomo.travaglini@arm.comtime. Therefore you'll get a different order every time. The console 191013481Sgiacomo.travaglini@arm.comoutput includes the random seed value, such that you can reproduce an 191113481Sgiacomo.travaglini@arm.comorder-related test failure later. To specify the random seed 191213481Sgiacomo.travaglini@arm.comexplicitly, use the `--gtest_random_seed=SEED` flag (or set the 191313481Sgiacomo.travaglini@arm.com`GTEST_RANDOM_SEED` environment variable), where `SEED` is an integer 191413481Sgiacomo.travaglini@arm.combetween 0 and 99999. The seed value 0 is special: it tells Google Test 191513481Sgiacomo.travaglini@arm.comto do the default behavior of calculating the seed from the current 191613481Sgiacomo.travaglini@arm.comtime. 191713481Sgiacomo.travaglini@arm.com 191813481Sgiacomo.travaglini@arm.comIf you combine this with `--gtest_repeat=N`, Google Test will pick a 191913481Sgiacomo.travaglini@arm.comdifferent random seed and re-shuffle the tests in each iteration. 192013481Sgiacomo.travaglini@arm.com 192113481Sgiacomo.travaglini@arm.com_Availability:_ Linux, Windows, Mac; since v1.4.0. 192213481Sgiacomo.travaglini@arm.com 192313481Sgiacomo.travaglini@arm.com## Controlling Test Output ## 192413481Sgiacomo.travaglini@arm.com 192513481Sgiacomo.travaglini@arm.comThis section teaches how to tweak the way test results are reported. 192613481Sgiacomo.travaglini@arm.com 192713481Sgiacomo.travaglini@arm.com### Colored Terminal Output ### 192813481Sgiacomo.travaglini@arm.com 192913481Sgiacomo.travaglini@arm.comGoogle Test can use colors in its terminal output to make it easier to spot 193013481Sgiacomo.travaglini@arm.comthe separation between tests, and whether tests passed. 193113481Sgiacomo.travaglini@arm.com 193213481Sgiacomo.travaglini@arm.comYou can set the GTEST\_COLOR environment variable or set the `--gtest_color` 193313481Sgiacomo.travaglini@arm.comcommand line flag to `yes`, `no`, or `auto` (the default) to enable colors, 193413481Sgiacomo.travaglini@arm.comdisable colors, or let Google Test decide. When the value is `auto`, Google 193513481Sgiacomo.travaglini@arm.comTest will use colors if and only if the output goes to a terminal and (on 193613481Sgiacomo.travaglini@arm.comnon-Windows platforms) the `TERM` environment variable is set to `xterm` or 193713481Sgiacomo.travaglini@arm.com`xterm-color`. 193813481Sgiacomo.travaglini@arm.com 193913481Sgiacomo.travaglini@arm.com_Availability:_ Linux, Windows, Mac. 194013481Sgiacomo.travaglini@arm.com 194113481Sgiacomo.travaglini@arm.com### Suppressing the Elapsed Time ### 194213481Sgiacomo.travaglini@arm.com 194313481Sgiacomo.travaglini@arm.comBy default, Google Test prints the time it takes to run each test. To 194413481Sgiacomo.travaglini@arm.comsuppress that, run the test program with the `--gtest_print_time=0` 194513481Sgiacomo.travaglini@arm.comcommand line flag. Setting the `GTEST_PRINT_TIME` environment 194613481Sgiacomo.travaglini@arm.comvariable to `0` has the same effect. 194713481Sgiacomo.travaglini@arm.com 194813481Sgiacomo.travaglini@arm.com_Availability:_ Linux, Windows, Mac. (In Google Test 1.3.0 and lower, 194913481Sgiacomo.travaglini@arm.comthe default behavior is that the elapsed time is **not** printed.) 195013481Sgiacomo.travaglini@arm.com 195113481Sgiacomo.travaglini@arm.com### Generating an XML Report ### 195213481Sgiacomo.travaglini@arm.com 195313481Sgiacomo.travaglini@arm.comGoogle Test can emit a detailed XML report to a file in addition to its normal 195413481Sgiacomo.travaglini@arm.comtextual output. The report contains the duration of each test, and thus can 195513481Sgiacomo.travaglini@arm.comhelp you identify slow tests. 195613481Sgiacomo.travaglini@arm.com 195713481Sgiacomo.travaglini@arm.comTo generate the XML report, set the `GTEST_OUTPUT` environment variable or the 195813481Sgiacomo.travaglini@arm.com`--gtest_output` flag to the string `"xml:_path_to_output_file_"`, which will 195913481Sgiacomo.travaglini@arm.comcreate the file at the given location. You can also just use the string 196013481Sgiacomo.travaglini@arm.com`"xml"`, in which case the output can be found in the `test_detail.xml` file in 196113481Sgiacomo.travaglini@arm.comthe current directory. 196213481Sgiacomo.travaglini@arm.com 196313481Sgiacomo.travaglini@arm.comIf you specify a directory (for example, `"xml:output/directory/"` on Linux or 196413481Sgiacomo.travaglini@arm.com`"xml:output\directory\"` on Windows), Google Test will create the XML file in 196513481Sgiacomo.travaglini@arm.comthat directory, named after the test executable (e.g. `foo_test.xml` for test 196613481Sgiacomo.travaglini@arm.comprogram `foo_test` or `foo_test.exe`). If the file already exists (perhaps left 196713481Sgiacomo.travaglini@arm.comover from a previous run), Google Test will pick a different name (e.g. 196813481Sgiacomo.travaglini@arm.com`foo_test_1.xml`) to avoid overwriting it. 196913481Sgiacomo.travaglini@arm.com 197013481Sgiacomo.travaglini@arm.comThe report uses the format described here. It is based on the 197113481Sgiacomo.travaglini@arm.com`junitreport` Ant task and can be parsed by popular continuous build 197213481Sgiacomo.travaglini@arm.comsystems like [Jenkins](http://jenkins-ci.org/). Since that format 197313481Sgiacomo.travaglini@arm.comwas originally intended for Java, a little interpretation is required 197413481Sgiacomo.travaglini@arm.comto make it apply to Google Test tests, as shown here: 197513481Sgiacomo.travaglini@arm.com 197613481Sgiacomo.travaglini@arm.com``` 197713481Sgiacomo.travaglini@arm.com<testsuites name="AllTests" ...> 197813481Sgiacomo.travaglini@arm.com <testsuite name="test_case_name" ...> 197913481Sgiacomo.travaglini@arm.com <testcase name="test_name" ...> 198013481Sgiacomo.travaglini@arm.com <failure message="..."/> 198113481Sgiacomo.travaglini@arm.com <failure message="..."/> 198213481Sgiacomo.travaglini@arm.com <failure message="..."/> 198313481Sgiacomo.travaglini@arm.com </testcase> 198413481Sgiacomo.travaglini@arm.com </testsuite> 198513481Sgiacomo.travaglini@arm.com</testsuites> 198613481Sgiacomo.travaglini@arm.com``` 198713481Sgiacomo.travaglini@arm.com 198813481Sgiacomo.travaglini@arm.com * The root `<testsuites>` element corresponds to the entire test program. 198913481Sgiacomo.travaglini@arm.com * `<testsuite>` elements correspond to Google Test test cases. 199013481Sgiacomo.travaglini@arm.com * `<testcase>` elements correspond to Google Test test functions. 199113481Sgiacomo.travaglini@arm.com 199213481Sgiacomo.travaglini@arm.comFor instance, the following program 199313481Sgiacomo.travaglini@arm.com 199413481Sgiacomo.travaglini@arm.com``` 199513481Sgiacomo.travaglini@arm.comTEST(MathTest, Addition) { ... } 199613481Sgiacomo.travaglini@arm.comTEST(MathTest, Subtraction) { ... } 199713481Sgiacomo.travaglini@arm.comTEST(LogicTest, NonContradiction) { ... } 199813481Sgiacomo.travaglini@arm.com``` 199913481Sgiacomo.travaglini@arm.com 200013481Sgiacomo.travaglini@arm.comcould generate this report: 200113481Sgiacomo.travaglini@arm.com 200213481Sgiacomo.travaglini@arm.com``` 200313481Sgiacomo.travaglini@arm.com<?xml version="1.0" encoding="UTF-8"?> 200413481Sgiacomo.travaglini@arm.com<testsuites tests="3" failures="1" errors="0" time="35" name="AllTests"> 200513481Sgiacomo.travaglini@arm.com <testsuite name="MathTest" tests="2" failures="1" errors="0" time="15"> 200613481Sgiacomo.travaglini@arm.com <testcase name="Addition" status="run" time="7" classname=""> 200713481Sgiacomo.travaglini@arm.com <failure message="Value of: add(1, 1)
 Actual: 3
Expected: 2" type=""/> 200813481Sgiacomo.travaglini@arm.com <failure message="Value of: add(1, -1)
 Actual: 1
Expected: 0" type=""/> 200913481Sgiacomo.travaglini@arm.com </testcase> 201013481Sgiacomo.travaglini@arm.com <testcase name="Subtraction" status="run" time="5" classname=""> 201113481Sgiacomo.travaglini@arm.com </testcase> 201213481Sgiacomo.travaglini@arm.com </testsuite> 201313481Sgiacomo.travaglini@arm.com <testsuite name="LogicTest" tests="1" failures="0" errors="0" time="5"> 201413481Sgiacomo.travaglini@arm.com <testcase name="NonContradiction" status="run" time="5" classname=""> 201513481Sgiacomo.travaglini@arm.com </testcase> 201613481Sgiacomo.travaglini@arm.com </testsuite> 201713481Sgiacomo.travaglini@arm.com</testsuites> 201813481Sgiacomo.travaglini@arm.com``` 201913481Sgiacomo.travaglini@arm.com 202013481Sgiacomo.travaglini@arm.comThings to note: 202113481Sgiacomo.travaglini@arm.com 202213481Sgiacomo.travaglini@arm.com * The `tests` attribute of a `<testsuites>` or `<testsuite>` element tells how many test functions the Google Test program or test case contains, while the `failures` attribute tells how many of them failed. 202313481Sgiacomo.travaglini@arm.com * The `time` attribute expresses the duration of the test, test case, or entire test program in milliseconds. 202413481Sgiacomo.travaglini@arm.com * Each `<failure>` element corresponds to a single failed Google Test assertion. 202513481Sgiacomo.travaglini@arm.com * Some JUnit concepts don't apply to Google Test, yet we have to conform to the DTD. Therefore you'll see some dummy elements and attributes in the report. You can safely ignore these parts. 202613481Sgiacomo.travaglini@arm.com 202713481Sgiacomo.travaglini@arm.com_Availability:_ Linux, Windows, Mac. 202813481Sgiacomo.travaglini@arm.com 202913481Sgiacomo.travaglini@arm.com## Controlling How Failures Are Reported ## 203013481Sgiacomo.travaglini@arm.com 203113481Sgiacomo.travaglini@arm.com### Turning Assertion Failures into Break-Points ### 203213481Sgiacomo.travaglini@arm.com 203313481Sgiacomo.travaglini@arm.comWhen running test programs under a debugger, it's very convenient if the 203413481Sgiacomo.travaglini@arm.comdebugger can catch an assertion failure and automatically drop into interactive 203513481Sgiacomo.travaglini@arm.commode. Google Test's _break-on-failure_ mode supports this behavior. 203613481Sgiacomo.travaglini@arm.com 203713481Sgiacomo.travaglini@arm.comTo enable it, set the `GTEST_BREAK_ON_FAILURE` environment variable to a value 203813481Sgiacomo.travaglini@arm.comother than `0` . Alternatively, you can use the `--gtest_break_on_failure` 203913481Sgiacomo.travaglini@arm.comcommand line flag. 204013481Sgiacomo.travaglini@arm.com 204113481Sgiacomo.travaglini@arm.com_Availability:_ Linux, Windows, Mac. 204213481Sgiacomo.travaglini@arm.com 204313481Sgiacomo.travaglini@arm.com### Disabling Catching Test-Thrown Exceptions ### 204413481Sgiacomo.travaglini@arm.com 204513481Sgiacomo.travaglini@arm.comGoogle Test can be used either with or without exceptions enabled. If 204613481Sgiacomo.travaglini@arm.coma test throws a C++ exception or (on Windows) a structured exception 204713481Sgiacomo.travaglini@arm.com(SEH), by default Google Test catches it, reports it as a test 204813481Sgiacomo.travaglini@arm.comfailure, and continues with the next test method. This maximizes the 204913481Sgiacomo.travaglini@arm.comcoverage of a test run. Also, on Windows an uncaught exception will 205013481Sgiacomo.travaglini@arm.comcause a pop-up window, so catching the exceptions allows you to run 205113481Sgiacomo.travaglini@arm.comthe tests automatically. 205213481Sgiacomo.travaglini@arm.com 205313481Sgiacomo.travaglini@arm.comWhen debugging the test failures, however, you may instead want the 205413481Sgiacomo.travaglini@arm.comexceptions to be handled by the debugger, such that you can examine 205513481Sgiacomo.travaglini@arm.comthe call stack when an exception is thrown. To achieve that, set the 205613481Sgiacomo.travaglini@arm.com`GTEST_CATCH_EXCEPTIONS` environment variable to `0`, or use the 205713481Sgiacomo.travaglini@arm.com`--gtest_catch_exceptions=0` flag when running the tests. 205813481Sgiacomo.travaglini@arm.com 205913481Sgiacomo.travaglini@arm.com**Availability**: Linux, Windows, Mac. 206013481Sgiacomo.travaglini@arm.com 206113481Sgiacomo.travaglini@arm.com### Letting Another Testing Framework Drive ### 206213481Sgiacomo.travaglini@arm.com 206313481Sgiacomo.travaglini@arm.comIf you work on a project that has already been using another testing 206413481Sgiacomo.travaglini@arm.comframework and is not ready to completely switch to Google Test yet, 206513481Sgiacomo.travaglini@arm.comyou can get much of Google Test's benefit by using its assertions in 206613481Sgiacomo.travaglini@arm.comyour existing tests. Just change your `main()` function to look 206713481Sgiacomo.travaglini@arm.comlike: 206813481Sgiacomo.travaglini@arm.com 206913481Sgiacomo.travaglini@arm.com``` 207013481Sgiacomo.travaglini@arm.com#include "gtest/gtest.h" 207113481Sgiacomo.travaglini@arm.com 207213481Sgiacomo.travaglini@arm.comint main(int argc, char** argv) { 207313481Sgiacomo.travaglini@arm.com ::testing::GTEST_FLAG(throw_on_failure) = true; 207413481Sgiacomo.travaglini@arm.com // Important: Google Test must be initialized. 207513481Sgiacomo.travaglini@arm.com ::testing::InitGoogleTest(&argc, argv); 207613481Sgiacomo.travaglini@arm.com 207713481Sgiacomo.travaglini@arm.com ... whatever your existing testing framework requires ... 207813481Sgiacomo.travaglini@arm.com} 207913481Sgiacomo.travaglini@arm.com``` 208013481Sgiacomo.travaglini@arm.com 208113481Sgiacomo.travaglini@arm.comWith that, you can use Google Test assertions in addition to the 208213481Sgiacomo.travaglini@arm.comnative assertions your testing framework provides, for example: 208313481Sgiacomo.travaglini@arm.com 208413481Sgiacomo.travaglini@arm.com``` 208513481Sgiacomo.travaglini@arm.comvoid TestFooDoesBar() { 208613481Sgiacomo.travaglini@arm.com Foo foo; 208713481Sgiacomo.travaglini@arm.com EXPECT_LE(foo.Bar(1), 100); // A Google Test assertion. 208813481Sgiacomo.travaglini@arm.com CPPUNIT_ASSERT(foo.IsEmpty()); // A native assertion. 208913481Sgiacomo.travaglini@arm.com} 209013481Sgiacomo.travaglini@arm.com``` 209113481Sgiacomo.travaglini@arm.com 209213481Sgiacomo.travaglini@arm.comIf a Google Test assertion fails, it will print an error message and 209313481Sgiacomo.travaglini@arm.comthrow an exception, which will be treated as a failure by your host 209413481Sgiacomo.travaglini@arm.comtesting framework. If you compile your code with exceptions disabled, 209513481Sgiacomo.travaglini@arm.coma failed Google Test assertion will instead exit your program with a 209613481Sgiacomo.travaglini@arm.comnon-zero code, which will also signal a test failure to your test 209713481Sgiacomo.travaglini@arm.comrunner. 209813481Sgiacomo.travaglini@arm.com 209913481Sgiacomo.travaglini@arm.comIf you don't write `::testing::GTEST_FLAG(throw_on_failure) = true;` in 210013481Sgiacomo.travaglini@arm.comyour `main()`, you can alternatively enable this feature by specifying 210113481Sgiacomo.travaglini@arm.comthe `--gtest_throw_on_failure` flag on the command-line or setting the 210213481Sgiacomo.travaglini@arm.com`GTEST_THROW_ON_FAILURE` environment variable to a non-zero value. 210313481Sgiacomo.travaglini@arm.com 210413481Sgiacomo.travaglini@arm.comDeath tests are _not_ supported when other test framework is used to organize tests. 210513481Sgiacomo.travaglini@arm.com 210613481Sgiacomo.travaglini@arm.com_Availability:_ Linux, Windows, Mac; since v1.3.0. 210713481Sgiacomo.travaglini@arm.com 210813481Sgiacomo.travaglini@arm.com## Distributing Test Functions to Multiple Machines ## 210913481Sgiacomo.travaglini@arm.com 211013481Sgiacomo.travaglini@arm.comIf you have more than one machine you can use to run a test program, 211113481Sgiacomo.travaglini@arm.comyou might want to run the test functions in parallel and get the 211213481Sgiacomo.travaglini@arm.comresult faster. We call this technique _sharding_, where each machine 211313481Sgiacomo.travaglini@arm.comis called a _shard_. 211413481Sgiacomo.travaglini@arm.com 211513481Sgiacomo.travaglini@arm.comGoogle Test is compatible with test sharding. To take advantage of 211613481Sgiacomo.travaglini@arm.comthis feature, your test runner (not part of Google Test) needs to do 211713481Sgiacomo.travaglini@arm.comthe following: 211813481Sgiacomo.travaglini@arm.com 211913481Sgiacomo.travaglini@arm.com 1. Allocate a number of machines (shards) to run the tests. 212013481Sgiacomo.travaglini@arm.com 1. On each shard, set the `GTEST_TOTAL_SHARDS` environment variable to the total number of shards. It must be the same for all shards. 212113481Sgiacomo.travaglini@arm.com 1. On each shard, set the `GTEST_SHARD_INDEX` environment variable to the index of the shard. Different shards must be assigned different indices, which must be in the range `[0, GTEST_TOTAL_SHARDS - 1]`. 212213481Sgiacomo.travaglini@arm.com 1. Run the same test program on all shards. When Google Test sees the above two environment variables, it will select a subset of the test functions to run. Across all shards, each test function in the program will be run exactly once. 212313481Sgiacomo.travaglini@arm.com 1. Wait for all shards to finish, then collect and report the results. 212413481Sgiacomo.travaglini@arm.com 212513481Sgiacomo.travaglini@arm.comYour project may have tests that were written without Google Test and 212613481Sgiacomo.travaglini@arm.comthus don't understand this protocol. In order for your test runner to 212713481Sgiacomo.travaglini@arm.comfigure out which test supports sharding, it can set the environment 212813481Sgiacomo.travaglini@arm.comvariable `GTEST_SHARD_STATUS_FILE` to a non-existent file path. If a 212913481Sgiacomo.travaglini@arm.comtest program supports sharding, it will create this file to 213013481Sgiacomo.travaglini@arm.comacknowledge the fact (the actual contents of the file are not 213113481Sgiacomo.travaglini@arm.comimportant at this time; although we may stick some useful information 213213481Sgiacomo.travaglini@arm.comin it in the future.); otherwise it will not create it. 213313481Sgiacomo.travaglini@arm.com 213413481Sgiacomo.travaglini@arm.comHere's an example to make it clear. Suppose you have a test program 213513481Sgiacomo.travaglini@arm.com`foo_test` that contains the following 5 test functions: 213613481Sgiacomo.travaglini@arm.com``` 213713481Sgiacomo.travaglini@arm.comTEST(A, V) 213813481Sgiacomo.travaglini@arm.comTEST(A, W) 213913481Sgiacomo.travaglini@arm.comTEST(B, X) 214013481Sgiacomo.travaglini@arm.comTEST(B, Y) 214113481Sgiacomo.travaglini@arm.comTEST(B, Z) 214213481Sgiacomo.travaglini@arm.com``` 214313481Sgiacomo.travaglini@arm.comand you have 3 machines at your disposal. To run the test functions in 214413481Sgiacomo.travaglini@arm.comparallel, you would set `GTEST_TOTAL_SHARDS` to 3 on all machines, and 214513481Sgiacomo.travaglini@arm.comset `GTEST_SHARD_INDEX` to 0, 1, and 2 on the machines respectively. 214613481Sgiacomo.travaglini@arm.comThen you would run the same `foo_test` on each machine. 214713481Sgiacomo.travaglini@arm.com 214813481Sgiacomo.travaglini@arm.comGoogle Test reserves the right to change how the work is distributed 214913481Sgiacomo.travaglini@arm.comacross the shards, but here's one possible scenario: 215013481Sgiacomo.travaglini@arm.com 215113481Sgiacomo.travaglini@arm.com * Machine #0 runs `A.V` and `B.X`. 215213481Sgiacomo.travaglini@arm.com * Machine #1 runs `A.W` and `B.Y`. 215313481Sgiacomo.travaglini@arm.com * Machine #2 runs `B.Z`. 215413481Sgiacomo.travaglini@arm.com 215513481Sgiacomo.travaglini@arm.com_Availability:_ Linux, Windows, Mac; since version 1.3.0. 215613481Sgiacomo.travaglini@arm.com 215713481Sgiacomo.travaglini@arm.com# Fusing Google Test Source Files # 215813481Sgiacomo.travaglini@arm.com 215913481Sgiacomo.travaglini@arm.comGoogle Test's implementation consists of ~30 files (excluding its own 216013481Sgiacomo.travaglini@arm.comtests). Sometimes you may want them to be packaged up in two files (a 216113481Sgiacomo.travaglini@arm.com`.h` and a `.cc`) instead, such that you can easily copy them to a new 216213481Sgiacomo.travaglini@arm.commachine and start hacking there. For this we provide an experimental 216313481Sgiacomo.travaglini@arm.comPython script `fuse_gtest_files.py` in the `scripts/` directory (since release 1.3.0). 216413481Sgiacomo.travaglini@arm.comAssuming you have Python 2.4 or above installed on your machine, just 216513481Sgiacomo.travaglini@arm.comgo to that directory and run 216613481Sgiacomo.travaglini@arm.com``` 216713481Sgiacomo.travaglini@arm.compython fuse_gtest_files.py OUTPUT_DIR 216813481Sgiacomo.travaglini@arm.com``` 216913481Sgiacomo.travaglini@arm.com 217013481Sgiacomo.travaglini@arm.comand you should see an `OUTPUT_DIR` directory being created with files 217113481Sgiacomo.travaglini@arm.com`gtest/gtest.h` and `gtest/gtest-all.cc` in it. These files contain 217213481Sgiacomo.travaglini@arm.comeverything you need to use Google Test. Just copy them to anywhere 217313481Sgiacomo.travaglini@arm.comyou want and you are ready to write tests. You can use the 217413481Sgiacomo.travaglini@arm.com[scripts/test/Makefile](../scripts/test/Makefile) 217513481Sgiacomo.travaglini@arm.comfile as an example on how to compile your tests against them. 217613481Sgiacomo.travaglini@arm.com 217713481Sgiacomo.travaglini@arm.com# Where to Go from Here # 217813481Sgiacomo.travaglini@arm.com 217913481Sgiacomo.travaglini@arm.comCongratulations! You've now learned more advanced Google Test tools and are 218013481Sgiacomo.travaglini@arm.comready to tackle more complex testing tasks. If you want to dive even deeper, you 218113481Sgiacomo.travaglini@arm.comcan read the [Frequently-Asked Questions](V1_7_FAQ.md). 2182