travis: run tests on macOS

[jirikuncar]

Closes #3892
Closes #3888

Thanks for submitting a PR, your contribution is really appreciated!

Here's a quick checklist that should be present in PRs (you can delete this text from the final description, this is
just a guideline):

• Create a new changelog file in the changelog folder, with a name like <ISSUE NUMBER>.<TYPE>.rst. See changelog/README.rst for details.
• Target the master branch for bug fixes, documentation updates and trivial changes.
• Target the features branch for new features and removals/deprecations.
• Include documentation when adding new features.
• Include new tests or update existing tests when applicable.

Unless your change is trivial or a small documentation fix (e.g., a typo or reword of a small section) please:

• Add yourself to AUTHORS in alphabetical order; trivial change - no code

[nicoddemus]

Awesome. 😎

Is python2.7 available on this image? If so, is it worth it to also test on 2.7?

[jirikuncar]

python2.7 is the system Python. We can include it too.

[nicoddemus]

Please let's do it then. 👍

[coveralls]

Coverage increased (+0.04%) to 92.622% when pulling 32575f9 on jirikuncar:3892-macos into 2a059b1 on pytest-dev:master.

[nicoddemus]

@jirikuncar the build failed with:

/Users/travis/.travis/job_stages: line 78: tox: command not found

Can you install tox with brew?

Btw, feel free to comment out the other environments until we get OS-X running, so the builds are faster. 👍

[codecov]

Codecov Report

Merging #3893 into master will increase coverage by 0.04%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master    #3893      +/-   ##
==========================================
+ Coverage   92.58%   92.62%   +0.04%     
==========================================
  Files          51       51              
  Lines        9960     9961       +1     
==========================================
+ Hits         9221     9226       +5     
+ Misses        739      735       -4

Impacted Files	Coverage Δ
src/_pytest/doctest.py	93.17% <0%> (-0.38%)	⬇️
src/_pytest/terminal.py	94.23% <0%> (+0.92%)	⬆️

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[blueyed]

Should not be defined in the "included" part probably ("&test-macos").

[nicoddemus]

done

[jirikuncar]

It's good to have a default which get changed later.

[blueyed]

Doesn't the normal "install" suffice? (also above)

[nicoddemus]

@jirikuncar I force-pushed to your branch to remove a temporary commit, hope that's OK.

I've fixed the failing test and dropped py36 from OS-X: in my experience Travis OS-X jobs take longer (sometimes a lot longer) to start than plain linux jobs, and I think testing with py27 and py37 is enough to ensure compatibility. 👍

[jni]

Thanks everyone for the fast response here! Can I ask whether a patch release will be made soon (e.g. ~1 week timeframe)? We need to decide whether to pin to an earlier pytest or wait for this fix in our own repo.

[nicoddemus]

@jni we strive to make bug fix releases every 2 weeks or so, but we can make an exception and cut a release sooner, no problem. But regardless I would suggest to pin pytest to an earlier version, otherwise your PRs will be broken until then.

[jirikuncar]

@jni I have personally changed my dependency to pytest>=3.6.3,!=3.7.3 so I get the latest update when it is ready.

[jni]

Thanks everyone! Yes this episode has taught me that != is a valid pip limiter. =) Which is what I was after, something that would not pull in 3.7.3 but would not prevent future updates.

@nicoddemus the reason I was asking is that our project is pretty slow moving at the moment and I can't reliably predict that we will merge a fix before 3.7.4 is out. =P