DM-16296: Remove escape of % in string

[timj]

This was generating a flake8 warning before.

[parejkoj]

Assuming this really does work, looks fine to me.

[timj]

@parejkoj I've tweaked the PR to also use automatic file detection in pytest to be consistent with other packages. Running on Jenkins now.

[parejkoj]

Why did you remove the full directory tests/data/ from the ignore list? Everything in there should be ignored, always.

[timj]

There's only one python file in there and I couldn't get it to work with the wildcard.

[parejkoj]

Even tests/data/* didn't work? or *.py? That's unfortunate, but I guess we can live with it.

Separately, why remove jointcalTestBase.py from the tests ignore list? I think including it results in a false unused test or something (because it's just the base classes, no tests itself).

[timj]

pytest only looks for test_X.py files for testing. sconsUtils looks for all .py files. Since I switched to using pytest file detection I don't need to ignore the file (and ignoring the file is ignored if using pytest).