pytest-deadfixtures

3.1.0 · active · verified Mon Apr 13

pytest-deadfixtures is a simple plugin for pytest that helps identify unused or duplicated fixtures within your test suite. It aids in improving code quality by highlighting fixtures that are no longer needed or could be refactored. The current version is 3.1.0, and the library appears to be actively maintained with a consistent release cadence.

Warnings

breaking Version 3.0.0 dropped support for Python 3.5. Ensure your environment uses Python 3.6 or newer.
Fix: Upgrade Python version to 3.6 or higher.
gotcha The `--dead-fixtures` option *does not run your tests*. It is sensitive to errors in the pytest collection step. For CI/CD, it's recommended to run `pytest --dead-fixtures` *after* a successful default `pytest` run.
Fix: In your CI pipeline, execute `pytest` first, then a separate command `pytest --dead-fixtures` to ensure test functionality is verified before checking for unused fixtures.
gotcha When using `--dup-fixtures` to find duplicated fixtures, the plugin relies on comparing fixture *return values*. Fixtures that return `None` or other falsy values will be skipped from this analysis. This feature should be used as a hint for manual verification.
Fix: Manually verify any reported duplicated fixtures, especially those that return falsy values, to confirm they are truly redundant.
gotcha By default, the plugin returns a non-zero exit code if unused fixtures are detected (since version 2.0.0). This will cause CI pipelines to fail if any unused fixtures are found.
Fix: Either remove the reported unused fixtures, mark them with `@deadfixtures_ignore`, or configure your CI to allow this specific failure code if you do not want it to be a blocking issue.
gotcha pytest-deadfixtures primarily relies on static analysis to detect unused fixtures. It might not correctly identify fixtures used dynamically (e.g., via `request.getfixturevalue()` or other advanced runtime mechanisms).
Fix: For fixtures potentially used dynamically, consider applying the `@deadfixtures_ignore` decorator to prevent false positives, or manually verify their usage.

Install

pip install pytest-deadfixtures Install stable version

Imports

deadfixtures_ignore
```
from pytest_deadfixtures import deadfixtures_ignore
```
Used to explicitly mark fixtures that should not be reported as unused.

Quickstart

To use `pytest-deadfixtures`, install the plugin and then run pytest with the `--dead-fixtures` command-line option. The plugin will analyze your test suite and report any fixtures it identifies as unused. You can optionally use `--dup-fixtures` to find duplicated fixtures or `--show-ignored-fixtures` to list fixtures that have been explicitly ignored. The `deadfixtures_ignore` decorator can be applied to fixtures you intend to leave unused.

import pytest
from pytest_deadfixtures import deadfixtures_ignore

@pytest.fixture
def used_fixture():
    return "I am used"

@pytest.fixture
def unused_fixture():
    """This fixture is intentionally unused for demonstration."""
    return "I am not used"

@pytest.fixture
@deadfixtures_ignore
def ignored_fixture():
    """This fixture will be explicitly ignored by the plugin."""
    return "I am ignored"

def test_example(used_fixture):
    assert used_fixture == "I am used"

# To run this example and see the unused fixture report, save it as a Python file (e.g., test_fixtures.py)
# and execute from your terminal:
# pytest --dead-fixtures --show-ignored-fixtures -v test_fixtures.py

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