2021-11-08 PyAerocom meeting

[avaldebe]

Add lint job to CI

Uniform formatting is helpful, in general, but it might take some time to adjust to the new format standard. With the right configurations, IDEs can format python files on save, helping to integrate the new formatting tools to the development workflow.

Álvaro shows the new jobs added to CI by PR #397, implemented with tox. This way the same commands can be run locally and on CI:

tox -e py38	# run the test suite for Python 3.8
tox -e py39	# run the test suite for Python 3.9
tox -e docs	# build the documentation: 
tox -e format	# check the formatting with black and isort
tox -e lint	# run type checker and linter (mypy, pylint, &c)

PRs started before the code formatting was imposed might have problem to merge, as
PR #397 formats the complete code base in order to pass the format checkers.

Hans and Daniel could not attend this meeting (Álvaro forgot to set the video conference, so Hans could not join). Álvaro will contact them and explain the benefits and potential problems for old PRs.

Tests as development documentation

In a perfect world, tests provide examples of the functionality provided by different modules, classes and methods (AKA the happy path), and examples of misuse that will stop the execution with an unhandled exception (AKA the unhappy path).
The test suite is relatively new, and was developed to provide the best coverage possible in a short time. Here the happy and unhappy paths are addressed on the same test function.
Álvaro shows some examples of such test functions. How to split the happy/unhappy paths onto different functions, resulting on simpler and more readable tests.

Next meeting

Álvaro will talk more about testing...