--report-type='' implies no --cov-fail-under

[terencehonles]

Specifying --cov-report= will not output any report information and will not check minimum coverage which may be specified with --cov-fail-under=MIN or through the config. This change is to allow using --cov-append in future runs without reporting failure too early.

With this change, on the final build you will need to generate at least --cov-report=term or run coverage report directly

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I made this change because I want to declare fail_under in my coverage config (for me it lives in setup.cfg which passes some other common options by using addopts (like mentioned in #195)), but my current test setup requires at least 2 passes running pytest which initially the sequence would be:

ENV_VAR=value pytest --cov-report=
ENV_VAR=other_value pytest --cov-append

However, without the proposed PR the first test fails and I would have to ignore the exit code (which is not appropriate because the test suite may have actually failed)

With this change I can leave fail_under as part of my coverage config instead of having to hardcode it in the CI runner or add an additional file/configuration option.

[ionelmc]

Hmm.. shouldn't we have a negative option, like --cov-disable-reporting ?

I wonder if users will trip up on this empty value (eg: they forget the = - --cov-report tests.py will have undesirable result).

[terencehonles]

@ionelmc I'm up for whatever. I've actually re-worked our system to not need two test passes, but I'm willing to alter this to help whoever may need this in the future.

[ionelmc]

@terencehonles agree to just close this? It doesn't sound like you or anyone needs this anymore ...

[graingert]

@terencehonles you can actually just set:

ENV_VAR=value pytest --cov-fail-under=0
ENV_VAR=other_value pytest --cov-append

[terencehonles]

@graingert are you sure that works? IIRC I tried that and the value in setup.cfg took precedence to that.

[terencehonles]

Well it does seem like the command line flag is working now, so not sure if something changed or I didn't actually try this. Either way, if that works this PR is unnecessary