Modules-specific tests can be written under respective module folders.
Each module should have "tests" folder created with the tests implemented
as `doctest` headers, so they can be collected by the buildsystem and
included directly in `tests/test_main.cpp` to be compiled.
Configured for a max line length of 120 characters.
psf/black is very opinionated and purposely doesn't leave much room for
configuration. The output is mostly OK so that should be fine for us,
but some things worth noting:
- Manually wrapped strings will be reflowed, so by using a line length
of 120 for the sake of preserving readability for our long command
calls, it also means that some manually wrapped strings are back on
the same line and should be manually merged again.
- Code generators using string concatenation extensively look awful,
since black puts each operand on a single line. We need to refactor
these generators to use more pythonic string formatting, for which
many options are available (`%`, `format` or f-strings).
- CI checks and a pre-commit hook will be added to ensure that future
buildsystem changes are well-formatted.
We already had `MODULE_*_ENABLED` defines but only in the modules
environment, and a few custom `*_ENABLED` defines in the main env
when we needed the information in core.
Now this is defined in a single header which can be included in the
files that need this information.
