Thank you for starting this @515hikaru . Are you interested in doing this same work for the other tests?

You can get a list of all failing tests with by looking at the "Warnings Summary" in one of the Travis CI logs. You could also change the pytest version here:

https://github.com/dask/dask/blob/master/continuous_integration/travis/install.sh#L54

@mrocklin: Thank you for your information. I want to fix other tests.

I will change pytest version when all tests fixed.

I fixed all tests, and changed pytest version in travis job.

Although travis 3rd job fails, I do not know how to fix it.It seems this issue is another one, is not it?

Yes, it's unrelated and being handled in #4276 . Merging this now. Thank you @515hikaru !

If you want to continue with this work the other Dask repositories like dask/distributed and dask/dask-ml probably also have this same problem.

I also notice that this is your first code contribution to this repository. Welcome!