Investigate using Hypothesis for some tests

[TomAugspurger]

Hypothesis recently added support for generating pandas objects: http://hypothesis.readthedocs.io/en/latest/numpy.html#pandas

This could be useful for testing some of the higher-level methods like melt, merge, etc.

Are there any objections to adding some hypothesis-based tests to our test suite? Is anyone familiar with hypothesis and interested in putting together examples of how we could use it?

[TomAugspurger]

As another example, I could see Hypothesis being very useful for something like #13432 (buggy index set ops for duplicates, non monotonic, categorical)

[shoyer]

This sounds like it's definitely worth trying! Is there a guarantee that the test cases it produces will always be the same? (Non-reproducible tests could be pretty painful.)

[TomAugspurger]

I believe that once a failing test case is found it's cached (somehow, not sure on the details.)

…

On Wed, Oct 25, 2017 at 10:49 AM, Stephan Hoyer ***@***.***> wrote: This sounds like it's definitely worth trying! Is there a guarantee that the test cases it produces will always be the same? (Non-reproducible tests could be pretty painful.) — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#17978 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ABQHIvYHXq8I4yFc8irTLznyt0jUidU7ks5sv1h7gaJpZM4QF4u7> .

[jbrockmendel]

A test database is kept in a .hypothesis directory. Not sure if that plays nicely with CI.

[jbrockmendel]

@TomAugspurger did this idea ever go anywhere? I'm thinking this might be a useful for testing offsets.

[TomAugspurger]

Don't think so, go for it!