Testing

You should write tests as you write code – not as an afterthought once the project is complete.

See also

File naming and directory layout for tests

Write tests

Test code tends to be written once and only read when the test fails. As a result, test code tends to be poorly written, with a lot of copy-pasting between test methods, which makes intent unclear.

To write clear tests:

• Test one scenario per test.

• Name tests, fixtures, and mocks descriptively. Do not suffix them 1, 2, 3, etc.

• Use pytest.mark.parametrize to test something with different inputs (like in OCDS Kit).

• Use pytest.fixture to re-use test scaffolding (like in OCDS Merge or Kingfisher Colab).

• Use unittest.TestCase to re-use testing logic, including:

  • Test methods (like ViewTests in Toucan)

  • Test scaffolding, using setUp() and tearDown()

• Use subTest() from unittest (with pytest-subtests if using pytest) to reduce duplication (like in Pelican backend).

Note

There are important caveats to using pytest with unittest.

Run tests

For Django applications:

python manage.py test

Otherwise, pytest is preferred. For applications:

pip-sync requirements_dev.txt
pytest

For packages:

pip install .[test]
pytest