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pytest Helpers

The pytest helpers keep session functions short while still letting you pass through nox positional arguments and custom environment variables. They are a thin layer over pytest, not a new test runner API.

liblaf.nox_recipes.pytest 

pytest(
    s: Session,
    *,
    cov: bool = True,
    eager_import: bool = True,
    env: Mapping[str, str | None] | None = None,
    suppress_no_test_exit_code: bool = False,
) -> None

Run pytest for the current session.

Parameters:

  • s

    (Session) –

    The active nox session.

  • cov

    (bool, default: True ) –

    Whether to pass --cov to pytest.

  • eager_import

    (bool, default: True ) –

    Whether to set EAGER_IMPORT=1 for the test command.

  • env

    (Mapping[str, str | None] | None, default: None ) –

    Extra environment variables merged into the pytest process.

  • suppress_no_test_exit_code

    (bool, default: False ) –

    Whether to treat pytest exit code 5 ("no tests collected") as a successful run.

Source code in src/liblaf/nox_recipes/_pytest.py 
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def pytest(
    s: nox.Session,
    *,
    cov: bool = True,
    eager_import: bool = True,
    env: Mapping[str, str | None] | None = None,
    suppress_no_test_exit_code: bool = False,
) -> None:
    """Run `pytest` for the current session.

    Args:
        s:
            The active `nox` session.
        cov:
            Whether to pass `--cov` to `pytest`.
        eager_import:
            Whether to set `EAGER_IMPORT=1` for the test command.
        env:
            Extra environment variables merged into the `pytest` process.
        suppress_no_test_exit_code:
            Whether to treat `pytest` exit code `5` ("no tests collected") as a
            successful run.
    """
    options: list[StrPath] = []
    if cov:
        options.append("--cov")
    _pytest(
        s,
        *options,
        eager_import=eager_import,
        env=env,
        suppress_no_test_exit_code=suppress_no_test_exit_code,
    )

liblaf.nox_recipes.pytest_bench 

pytest_bench(
    s: Session,
    *,
    eager_import: bool = True,
    env: Mapping[str, str | None] | None = None,
    suppress_no_test_exit_code: bool = False,
) -> None

Run the benchmark subset with CodSpeed-friendly defaults.

This helper runs pytest -m benchmark --codspeed. If pytest-xdist is installed in the session environment, it also adds --numprocesses=0 so benchmarks stay single-process and deterministic.

Parameters:

  • s

    (Session) –

    The active nox session.

  • eager_import

    (bool, default: True ) –

    Whether to set EAGER_IMPORT=1 for the test command.

  • env

    (Mapping[str, str | None] | None, default: None ) –

    Extra environment variables merged into the pytest process.

  • suppress_no_test_exit_code

    (bool, default: False ) –

    Whether to treat pytest exit code 5 ("no tests collected") as a successful run.

Source code in src/liblaf/nox_recipes/_pytest.py 
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def pytest_bench(
    s: nox.Session,
    *,
    eager_import: bool = True,
    env: Mapping[str, str | None] | None = None,
    suppress_no_test_exit_code: bool = False,
) -> None:
    """Run the benchmark subset with CodSpeed-friendly defaults.

    This helper runs `pytest -m benchmark --codspeed`. If `pytest-xdist` is
    installed in the session environment, it also adds `--numprocesses=0` so
    benchmarks stay single-process and deterministic.

    Args:
        s:
            The active `nox` session.
        eager_import:
            Whether to set `EAGER_IMPORT=1` for the test command.
        env:
            Extra environment variables merged into the `pytest` process.
        suppress_no_test_exit_code:
            Whether to treat `pytest` exit code `5` ("no tests collected") as a
            successful run.
    """
    options: list[StrPath] = ["-m", "benchmark", "--codspeed"]
    plugins: dict[str, str] = pytest_plugin_versions(s)
    if "pytest-xdist" in plugins:
        options.append("--numprocesses=0")
    _pytest(
        s,
        *options,
        eager_import=eager_import,
        env=env,
        suppress_no_test_exit_code=suppress_no_test_exit_code,
    )

liblaf.nox_recipes.pytest_plugin_versions 

pytest_plugin_versions(s: Session) -> dict[str, str]

Return installed pytest plugin versions for the session.

The result is parsed from pytest --version --version, which reports each discovered plugin on its own line.

Parameters:

  • s

    (Session) –

    The active nox session.

Returns:

  • dict[str, str] –

    A mapping of plugin distribution names to their installed versions.

Source code in src/liblaf/nox_recipes/_pytest.py 
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def pytest_plugin_versions(s: nox.Session) -> dict[str, str]:
    """Return installed `pytest` plugin versions for the session.

    The result is parsed from `pytest --version --version`, which reports each
    discovered plugin on its own line.

    Args:
        s:
            The active `nox` session.

    Returns:
        A mapping of plugin distribution names to their installed versions.
    """
    output: str = cast(
        "str", s.run_always("pytest", "--version", "--version", silent=True)
    )
    plugins: dict[str, str] = {}
    for line in output.splitlines():
        spec, at, _ = line.partition(" at ")
        if not at:
            continue
        plugin_name, _, plugin_version = spec.strip().rpartition("-")
        plugins[plugin_name] = plugin_version
    return plugins