pytest-depends

Common errors

• ModuleNotFoundError: No module named 'pytest_depends'

  cause The `pytest-depends` plugin is not installed in the current Python environment.
  fix Install the plugin using pip: `pip install pytest-depends`

• AttributeError: module 'pytest_depends' has no attribute 'depends'

  cause The `depends` decorator is typically imported via an alias from the top-level package, not directly as a submodule attribute, leading to an `AttributeError` if attempted.
  fix Import `pytest_depends` and alias it as `depends`: `import pytest_depends as depends`

• PytestCollectionWarning: Cannot find dependency 'missing_test_name' for '<test_node_id>'

  cause The dependency name specified in the `on` list of `@depends.depends()` does not correspond to an actual, discoverable test function name or pytest node ID.
  fix Double-check the string value(s) in `on=['your_dependency_name']`. It must be the exact name of the test function (e.g., `test_my_function`) or its full node ID for parameterized tests.

Warnings

• gotcha pytest-depends skips dependent tests if a dependency fails; it does not re-run the dependency or alter its outcome. A 'skipped' test is distinct from a 'failed' test.
  Fix: Understand that the dependent test will simply be marked SKIPPED by pytest, preventing its execution without attempting to correct or retry the failing dependency.
• gotcha The pytest-depends project has not been updated in over two years (since November 2021), which may lead to compatibility issues with newer versions of pytest or Python.
  Fix: Test thoroughly with your specific pytest and Python environment versions. If encountering issues, consider reviewing open issues on the GitHub repository or exploring alternative dependency management plugins for pytest.
• gotcha Dependency names provided in `@depends.depends(on=['...'])` must exactly match the test function names or their full pytest node IDs, including parameters for parameterized tests.
  Fix: Ensure the string in the 'on' list precisely corresponds to the target test function's name (e.g., `test_my_feature`) or its complete node ID if it's part of a parameterized set (e.g., `test_my_feature[param1-value]`).

Install

• pip install pytest-depends Install stable version

Imports

• depends
  wrong:

  from pytest_depends import depends

  correct:

  import pytest_depends as depends

  The `depends` decorator is commonly imported via an alias from the top-level package.

Quickstart

This quickstart demonstrates defining dependent tests. `test_dependent_on_success_runs` will execute because its dependency `test_dependency_a_success` passes. `test_dependent_on_failure_is_skipped` will be marked as skipped by pytest because its dependency `test_dependency_b_failure` fails.

import pytest
import pytest_depends as depends

# This test will pass and its dependent will run
def test_dependency_a_success():
    print("\nRunning test_dependency_a_success")
    assert True

# This test will fail and its dependent will be skipped
def test_dependency_b_failure():
    print("\nRunning test_dependency_b_failure")
    assert False

@depends.depends(on=['test_dependency_a_success'])
def test_dependent_on_success_runs():
    print("\nRunning test_dependent_on_success_runs")
    assert True

@depends.depends(on=['test_dependency_b_failure'])
def test_dependent_on_failure_is_skipped():
    print("\nRunning test_dependent_on_failure_is_skipped (expected to be skipped)")
    # This assert will not be reached if the test is skipped
    assert True

# To run this example, save it as 'test_my_deps.py' and run 'pytest' from your terminal.