tests: Refactor the Gem5Fixture to derive from UniqueFixture

Gem5Fixture is used to define a fixture for building the gem5
binary. Most tests are expected to define their own Gem5Fixture,
however, as some might depend on the same binary (e.g.,
./build/ARM/gem5.opt), they will try to re-define a fixture for the
same target. This patchset changes Gem5Fixture to derive from
UniqueFixture.

In addition, this patchset changes the way global fixtures are
discovered to work with the new Gem5Fixture class. Instead of
enumerating them when test definitions are loaded, we do so after the
tests have been filtered according to specified tags (e.g., include
opt variant, exclude fast, debug variants).

Change-Id: Ie868a7e18ef6c3271f3c8a658229657cd43997cb
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/19251
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>

ext,tests: Add back failing exceptions

Change-Id: Idf4ba8a2a3888787abf33d1a4ac52fcf146ce732
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/17452
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>

tests,ext: Add skip_cleanup implementation for TempdirFixture

Change-Id: Idc5ec9309a4ef3c0ad0c7e8b2df47294acc97ec4
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/17451
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>

ext,tests: Make return code based on test results

This patch also fixes a spelling mistake.

Change-Id: I8635216e512c10913a9cda54541d7e31e0d22a40
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/17450
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>

ext,test: Provide default terminal size

When creating the separator for printing things to the terminal (=.*) we
use an ioctl that isn't supported in some sandboxed environments. When
running on the Google jenkins server (kokoro) it errors with an IOError.

Change-Id: I148dd87cffe6e93d6723a386aecf9a9ea6c5b455
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/17449
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

testlib: No catch of custom exceptions in sandbox

Custom exceptions are not always properly pickled which could lead to
the sandbox test executor to crash when it tries to re __init__ pickled
exceptions thrown from the failed test.

Change-Id: I4e2ffe5802dda668b5d61c5a16e0989717121a04
Signed-off-by: Sean Wilson <spwilson27@gmail.com>
Reviewed-on: https://gem5-review.googlesource.com/12167
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

tests,ext: Add a new testing library proposal

The new test library is split into two parts: The framework which resides
in ext/, and the gem5 helping components in /tests/gem5.

Change-Id: Ib4f3ae8d7eb96a7306335a3e739b7e8041aa99b9
Signed-off-by: Sean Wilson <spwilson2@wisc.edu>
Reviewed-on: https://gem5-review.googlesource.com/4421
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>