Allow setting skip_covered to False for HTML

For CLI output it’s common to set skip-covered=True in the config file; however, in HTML export you want to set this False so you can see what test covers what line. There’s a new flag in this in the API:

  --no-skip-covered     Disable --skip-covered.

In this case https://github.com/pytest-dev/pytest-cov/blob/master/src/pytest_cov/engine.py#L189 should allow specifying as False (see skip_covered https://github.com/nedbat/coveragepy/blob/0b1dd531f23d8ba313ee685b156b07f76fa680d5/coverage/cmdline.py#L623). The one danger is that this flag needs to be somehow specified by the user. Potential options for this:

--cov html:out_dir:no-skip-covered

Should we perhaps set this always to False for HTML report? cc @asottile

PS. coveragepy ticket for perhaps a config side solution https://github.com/nedbat/coveragepy/issues/1090

[nedbat]

I really wish we could stop adding reporting options to pytest-cov, and just have people use the coverage reporting commands directly. There’s no need for pytest to produce coverage reports. It just leads to crazy command-line options like you are proposing.

[gaborbernat]

This now can be solved via https://github.com/nedbat/coveragepy/issues/1090