Best practice

Imports

  • Don’t use relative imports. Exceptions:

    • Skip namespace in __init__.py

  • Order the imports alphabetically

  • Do not use an alias of imports unless it’s a common one: import numpy as np

Pylint & Tests

  • Place an empty __init__.py into your test folder, otherwise pylint does not check the test-files.

Type hints

Unit Tests

  • A unit test has a descriptive name: test___unit_of_work___scenario___expected_behaviour

    • unit_of_work: What do I test?

    • scenario: How do I test?

    • expected_behaviour: What do I expect?

  • A unit test has in most cases three parts which are separated with a blank line:

    1. Arrange:
      Initialize all variables you need for the test, this includes also your expected values for the asserts at the end. Additionally, set up all necessary context which is needed for the test.
    2. Act:
      Run code under test. Keep this section small, run really only the function which you want to test. If the function relies on other functions to be called first, make sure they are already tested and call them for example in the fixture or as a part of Arrange.
    3. Assert:
      Check your expectations with asserts. Use whenever possible a specialized assert of your test-framework instead a generic one. For example:
      with pytest.raises(RuntimeError):
    parse_metadata('{}', mode=IoModes.STRICT)