Add inline documentation to WP_UnitTestCase

[anonymized_8769252]

The WP_UnitTestCase class is large, and complex, but it does not contain much inline documentation to make it easier to understand.

Let's change that.

[anonymized_8769252]

The patch above contains part one, as it's easier to do this in phases.

[netweb]

Looking good Frank, a couple of things:

• Can you update the patch to so that "back ported" is spelled as one word, i.e "backported" please
• I think the //error_log( $file ); comment should remain, it gives a quick heads up when debugging

[anonymized_8769252]

Thanks for the feedback, updated the patch.

Concerning the commented out //error_log( $file );, I agree that this should not be removed in a patch that adds inline documentation.

However I am convinced that it should not remain in the file, it should just be removed as part of another ticket. Leaving commented out code behind is like leaving litter on the floor of a public place.

[netweb]

Thanks for the updated patch, and that sounds like a plan +1

[johnbillion]

In 42379:

Build/Test tools: Add inline documentation to undocumented methods in the WP_UnitTestCase class.

Props Frank Klein

Fixes #42731