test_command_line_command_flag and test_command_line_import_flag: Different num_threads values

Start with test_command_line_command_flag and test_command_line_import_flag in tests/test_threadpoolctl.py, where the reported assertions compare command-line output with threadpool_info(). Check how the tests and command-line subprocess set or inherit thread counts, then determine whether the differing num_threads values indicate a code issue or an overly strict expectation. Done means the behavior is understood and the tests correctly reflect it.

Hello.

We are currently trying to rebuild this package in Fedora for Python 3.11, but we see some suspicious test failures that occur with Python 3.11 as well as with Python 3.10.

The failures look like this:

On i686:

________________________ test_command_line_command_flag ________________________
    def test_command_line_command_flag():
        pytest.importorskip("numpy")
        output = subprocess.check_output(
            [sys.executable, "-m", "threadpoolctl", "-c", "import numpy"]
        )
        cli_info = json.loads(output.decode("utf-8"))
    
        this_process_info = threadpool_info()
        for lib_info in cli_info:
>           assert lib_info in this_process_info
E           AssertionError: assert {'filepath': '/usr/lib/libgomp.so.1.0.0', 'internal_api': 'openmp', 'num_threads': 6, 'prefix': 'libgomp', ...} in [{'architecture': 'Nehalem', 'filepath': '/usr/lib/libopenblaso-r0.3.20.so', 'internal_api': 'openblas', 'num_threads': 30, ...}, {'filepath': '/usr/lib/libgomp.so.1.0.0', 'internal_api': 'openmp', 'num_threads': 30, 'prefix': 'libgomp', ...}]
tests/test_threadpoolctl.py:547: AssertionError
________________________ test_command_line_import_flag _________________________
    @pytest.mark.skipif(
        sys.version_info < (3, 7), reason="need recent subprocess.run options"
    )
    def test_command_line_import_flag():
        result = subprocess.run(
            [
                sys.executable,
                "-m",
                "threadpoolctl",
                "-i",
                "numpy",
                "scipy.linalg",
                "invalid_package",
                "numpy.invalid_sumodule",
            ],
            capture_output=True,
            check=True,
            encoding="utf-8",
        )
        cli_info = json.loads(result.stdout)
    
        this_process_info = threadpool_info()
        for lib_info in cli_info:
>           assert lib_info in this_process_info
E           AssertionError: assert {'filepath': '/usr/lib/libgomp.so.1.0.0', 'internal_api': 'openmp', 'num_threads': 6, 'prefix': 'libgomp', ...} in [{'architecture': 'Nehalem', 'filepath': '/usr/lib/libopenblaso-r0.3.20.so', 'internal_api': 'openblas', 'num_threads': 30, ...}, {'filepath': '/usr/lib/libgomp.so.1.0.0', 'internal_api': 'openmp', 'num_threads': 30, 'prefix': 'libgomp', ...}]
tests/test_threadpoolctl.py:573: AssertionError

On x86_64

________________________ test_command_line_command_flag ________________________
    def test_command_line_command_flag():
        pytest.importorskip("numpy")
        output = subprocess.check_output(
            [sys.executable, "-m", "threadpoolctl", "-c", "import numpy"]
        )
        cli_info = json.loads(output.decode("utf-8"))
    
        this_process_info = threadpool_info()
        for lib_info in cli_info:
>           assert lib_info in this_process_info
E           AssertionError: assert {'filepath': '/usr/lib64/libgomp.so.1.0.0', 'internal_api': 'openmp', 'num_threads': 6, 'prefix': 'libgomp', ...} in [{'architecture': 'SkylakeX', 'filepath': '/usr/lib64/libopenblaso-r0.3.20.so', 'internal_api': 'openblas', 'num_threads': 30, ...}, {'filepath': '/usr/lib64/libgomp.so.1.0.0', 'internal_api': 'openmp', 'num_threads': 30, 'prefix': 'libgomp', ...}]
tests/test_threadpoolctl.py:547: AssertionError
________________________ test_command_line_import_flag _________________________
    @pytest.mark.skipif(
        sys.version_info < (3, 7), reason="need recent subprocess.run options"
    )
    def test_command_line_import_flag():
        result = subprocess.run(
            [
                sys.executable,
                "-m",
                "threadpoolctl",
                "-i",
                "numpy",
                "scipy.linalg",
                "invalid_package",
                "numpy.invalid_sumodule",
            ],
            capture_output=True,
            check=True,
            encoding="utf-8",
        )
        cli_info = json.loads(result.stdout)
    
        this_process_info = threadpool_info()
        for lib_info in cli_info:
>           assert lib_info in this_process_info
E           AssertionError: assert {'filepath': '/usr/lib64/libgomp.so.1.0.0', 'internal_api': 'openmp', 'num_threads': 6, 'prefix': 'libgomp', ...} in [{'architecture': 'SkylakeX', 'filepath': '/usr/lib64/libopenblaso-r0.3.20.so', 'internal_api': 'openblas', 'num_threads': 30, ...}, {'filepath': '/usr/lib64/libgomp.so.1.0.0', 'internal_api': 'openmp', 'num_threads': 30, 'prefix': 'libgomp', ...}]
tests/test_threadpoolctl.py:573: AssertionError

On ppc64le

________________________ test_command_line_command_flag ________________________
    def test_command_line_command_flag():
        pytest.importorskip("numpy")
        output = subprocess.check_output(
            [sys.executable, "-m", "threadpoolctl", "-c", "import numpy"]
        )
        cli_info = json.loads(output.decode("utf-8"))
    
        this_process_info = threadpool_info()
        for lib_info in cli_info:
>           assert lib_info in this_process_info
E           AssertionError: assert {'filepath': '/usr/lib64/libgomp.so.1.0.0', 'internal_api': 'openmp', 'num_threads': 8, 'prefix': 'libgomp', ...} in [{'architecture': 'POWER9', 'filepath': '/usr/lib64/libopenblaso-r0.3.20.so', 'internal_api': 'openblas', 'num_threads': 40, ...}, {'filepath': '/usr/lib64/libgomp.so.1.0.0', 'internal_api': 'openmp', 'num_threads': 40, 'prefix': 'libgomp', ...}]
tests/test_threadpoolctl.py:547: AssertionError
________________________ test_command_line_import_flag _________________________
    @pytest.mark.skipif(
        sys.version_info < (3, 7), reason="need recent subprocess.run options"
    )
    def test_command_line_import_flag():
        result = subprocess.run(
            [
                sys.executable,
                "-m",
                "threadpoolctl",
                "-i",
                "numpy",
                "scipy.linalg",
                "invalid_package",
                "numpy.invalid_sumodule",
            ],
            capture_output=True,
            check=True,
            encoding="utf-8",
        )
        cli_info = json.loads(result.stdout)
    
        this_process_info = threadpool_info()
        for lib_info in cli_info:
>           assert lib_info in this_process_info
E           AssertionError: assert {'filepath': '/usr/lib64/libgomp.so.1.0.0', 'internal_api': 'openmp', 'num_threads': 8, 'prefix': 'libgomp', ...} in [{'architecture': 'POWER9', 'filepath': '/usr/lib64/libopenblaso-r0.3.20.so', 'internal_api': 'openblas', 'num_threads': 40, ...}, {'filepath': '/usr/lib64/libgomp.so.1.0.0', 'internal_api': 'openmp', 'num_threads': 40, 'prefix': 'libgomp', ...}]
tests/test_threadpoolctl.py:573: AssertionError

On s390x:

________________________ test_command_line_command_flag ________________________
    def test_command_line_command_flag():
        pytest.importorskip("numpy")
        output = subprocess.check_output(
            [sys.executable, "-m", "threadpoolctl", "-c", "import numpy"]
        )
        cli_info = json.loads(output.decode("utf-8"))
    
        this_process_info = threadpool_info()
        for lib_info in cli_info:
>           assert lib_info in this_process_info
E           AssertionError: assert {'filepath': '/usr/lib64/libgomp.so.1.0.0', 'internal_api': 'openmp', 'num_threads': 2, 'prefix': 'libgomp', ...} in [{'architecture': 'Z14', 'filepath': '/usr/lib64/libopenblaso-r0.3.20.so', 'internal_api': 'openblas', 'num_threads': 64, ...}, {'filepath': '/usr/lib64/libgomp.so.1.0.0', 'internal_api': 'openmp', 'num_threads': 64, 'prefix': 'libgomp', ...}]
tests/test_threadpoolctl.py:547: AssertionError
________________________ test_command_line_import_flag _________________________
    @pytest.mark.skipif(
        sys.version_info < (3, 7), reason="need recent subprocess.run options"
    )
    def test_command_line_import_flag():
        result = subprocess.run(
            [
                sys.executable,
                "-m",
                "threadpoolctl",
                "-i",
                "numpy",
                "scipy.linalg",
                "invalid_package",
                "numpy.invalid_sumodule",
            ],
            capture_output=True,
            check=True,
            encoding="utf-8",
        )
        cli_info = json.loads(result.stdout)
    
        this_process_info = threadpool_info()
        for lib_info in cli_info:
>           assert lib_info in this_process_info
E           AssertionError: assert {'filepath': '/usr/lib64/libgomp.so.1.0.0', 'internal_api': 'openmp', 'num_threads': 2, 'prefix': 'libgomp', ...} in [{'architecture': 'Z14', 'filepath': '/usr/lib64/libopenblaso-r0.3.20.so', 'internal_api': 'openblas', 'num_threads': 64, ...}, {'filepath': '/usr/lib64/libgomp.so.1.0.0', 'internal_api': 'openmp', 'num_threads': 64, 'prefix': 'libgomp', ...}]
tests/test_threadpoolctl.py:573: AssertionError

The tests pass on aarch64. test_architecture was skipped.

It appears the num_threads value is different. Is that a real problem or just bad test expectations? Thanks