test_callbacks.py revision 12391 
1import pytest
2from pybind11_tests import callbacks as m
3
4
5def test_callbacks():
6    from functools import partial
7
8    def func1():
9        return "func1"
10
11    def func2(a, b, c, d):
12        return "func2", a, b, c, d
13
14    def func3(a):
15        return "func3({})".format(a)
16
17    assert m.test_callback1(func1) == "func1"
18    assert m.test_callback2(func2) == ("func2", "Hello", "x", True, 5)
19    assert m.test_callback1(partial(func2, 1, 2, 3, 4)) == ("func2", 1, 2, 3, 4)
20    assert m.test_callback1(partial(func3, "partial")) == "func3(partial)"
21    assert m.test_callback3(lambda i: i + 1) == "func(43) = 44"
22
23    f = m.test_callback4()
24    assert f(43) == 44
25    f = m.test_callback5()
26    assert f(number=43) == 44
27
28
29def test_bound_method_callback():
30    # Bound Python method:
31    class MyClass:
32        def double(self, val):
33            return 2 * val
34
35    z = MyClass()
36    assert m.test_callback3(z.double) == "func(43) = 86"
37
38    z = m.CppBoundMethodTest()
39    assert m.test_callback3(z.triple) == "func(43) = 129"
40
41
42def test_keyword_args_and_generalized_unpacking():
43
44    def f(*args, **kwargs):
45        return args, kwargs
46
47    assert m.test_tuple_unpacking(f) == (("positional", 1, 2, 3, 4, 5, 6), {})
48    assert m.test_dict_unpacking(f) == (("positional", 1), {"key": "value", "a": 1, "b": 2})
49    assert m.test_keyword_args(f) == ((), {"x": 10, "y": 20})
50    assert m.test_unpacking_and_keywords1(f) == ((1, 2), {"c": 3, "d": 4})
51    assert m.test_unpacking_and_keywords2(f) == (
52        ("positional", 1, 2, 3, 4, 5),
53        {"key": "value", "a": 1, "b": 2, "c": 3, "d": 4, "e": 5}
54    )
55
56    with pytest.raises(TypeError) as excinfo:
57        m.test_unpacking_error1(f)
58    assert "Got multiple values for keyword argument" in str(excinfo.value)
59
60    with pytest.raises(TypeError) as excinfo:
61        m.test_unpacking_error2(f)
62    assert "Got multiple values for keyword argument" in str(excinfo.value)
63
64    with pytest.raises(RuntimeError) as excinfo:
65        m.test_arg_conversion_error1(f)
66    assert "Unable to convert call argument" in str(excinfo.value)
67
68    with pytest.raises(RuntimeError) as excinfo:
69        m.test_arg_conversion_error2(f)
70    assert "Unable to convert call argument" in str(excinfo.value)
71
72
73def test_lambda_closure_cleanup():
74    m.test_cleanup()
75    cstats = m.payload_cstats()
76    assert cstats.alive() == 0
77    assert cstats.copy_constructions == 1
78    assert cstats.move_constructions >= 1
79
80
81def test_cpp_function_roundtrip():
82    """Test if passing a function pointer from C++ -> Python -> C++ yields the original pointer"""
83
84    assert m.test_dummy_function(m.dummy_function) == "matches dummy_function: eval(1) = 2"
85    assert (m.test_dummy_function(m.roundtrip(m.dummy_function)) ==
86            "matches dummy_function: eval(1) = 2")
87    assert m.roundtrip(None, expect_none=True) is None
88    assert (m.test_dummy_function(lambda x: x + 2) ==
89            "can't convert to function pointer: eval(1) = 3")
90
91    with pytest.raises(TypeError) as excinfo:
92        m.test_dummy_function(m.dummy_function2)
93    assert "incompatible function arguments" in str(excinfo.value)
94
95    with pytest.raises(TypeError) as excinfo:
96        m.test_dummy_function(lambda x, y: x + y)
97    assert any(s in str(excinfo.value) for s in ("missing 1 required positional argument",
98                                                 "takes exactly 2 arguments"))
99
100
101def test_function_signatures(doc):
102    assert doc(m.test_callback3) == "test_callback3(arg0: Callable[[int], int]) -> str"
103    assert doc(m.test_callback4) == "test_callback4() -> Callable[[int], int]"
104
105
106def test_movable_object():
107    assert m.callback_with_movable(lambda _: None) is True
108