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System fixtures

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provide.testkit.process.system_fixtures

System-level process management fixtures for testing.

This module provides fixtures for managing system-level process behaviors during tests, including process title manipulation and system resource management.

Functions

disable_setproctitle 

disable_setproctitle() -> Generator[None, None, None]

Disables setproctitle during tests to prevent pytest-xdist performance issues.

The setproctitle module causes severe performance degradation when running tests with pytest-xdist parallelization: - Immediate slowdown on test start - Progressive performance degradation over time - High CPU usage due to frequent system calls

Mocks setproctitle as a no-op during regular test runs while preserving functionality for mutation testing tools like mutmut that use it for displaying progress information.

Autouse and session-scoped - applies automatically to all tests in a session.

Yields:

Name Type Description
None None

Context manager for test execution with setproctitle disabled
Note

Only disables setproctitle when NOT running under mutmut. Mutmut detection uses sys.argv to check for "mutmut" in arguments.

Source code in provide/testkit/process/system_fixtures.py 
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@pytest.fixture(scope="session", autouse=True)
def disable_setproctitle() -> Generator[None, None, None]:
    """Disables setproctitle during tests to prevent pytest-xdist performance issues.

    The setproctitle module causes severe performance degradation when running
    tests with pytest-xdist parallelization:
    - Immediate slowdown on test start
    - Progressive performance degradation over time
    - High CPU usage due to frequent system calls

    Mocks setproctitle as a no-op during regular test runs while preserving
    functionality for mutation testing tools like mutmut that use it for
    displaying progress information.

    Autouse and session-scoped - applies automatically to all tests in a session.

    Yields:
        None: Context manager for test execution with setproctitle disabled

    Note:
        Only disables setproctitle when NOT running under mutmut.
        Mutmut detection uses sys.argv to check for "mutmut" in arguments.
    """
    # Only disable if not running under mutmut
    # mutmut needs setproctitle to show which mutations are being tested
    if not any("mutmut" in arg for arg in sys.argv):
        # Check if setproctitle is already imported
        original_module = sys.modules.get("setproctitle")

        # Create a mock module with common setproctitle functions
        mock_setproctitle = MagicMock()
        mock_setproctitle.setproctitle = MagicMock(return_value=None)
        mock_setproctitle.getproctitle = MagicMock(return_value="python")
        mock_setproctitle.setthreadtitle = MagicMock(return_value=None)
        mock_setproctitle.getthreadtitle = MagicMock(return_value="")

        # Inject the mock into sys.modules before any imports
        sys.modules["setproctitle"] = mock_setproctitle

        try:
            yield
        finally:
            # Restore original module if it existed
            if original_module is not None:
                sys.modules["setproctitle"] = original_module
            elif "setproctitle" in sys.modules:
                del sys.modules["setproctitle"]
    else:
        # When running under mutmut, don't disable setproctitle
        yield