Add testing/__init__.py ?

[blueyed]

#6451 reminded me of having testing/__init__.py, which is required for specific mypy config ([mypy-testing.*]) - mypy requires this to be a module.

Should we add this?
We do not have specific mypy config for tests yet, but this would allow to use check_untyped_defs = True there then.

/cc @bluetech

[nicoddemus]

I'm not against adding testing/__init__.py at all, but it would probably better to do this until we have an actual reason to do so (that's if I understand your original message correctly in the first place).

[bluetech]

If there is a problem with adding actual testing/__init__.py, can always use testing/__init__.pyi (note the i at the end) to please mypy but not affect anything else.

[blueyed]

@bluetech that makes sense, thanks!