use keep_attrs in binary operations II

[MBlaschek]

• Closes Keep attributes across operations #2582
• Tests added (test_binary_ops_keep_attrs)

Please revise and advise.

[pep8speaks]

Hello @MBlaschek! Thanks for updating the PR.

• There are no PEP8 issues in the file xarray/core/variable.py !

• There are no PEP8 issues in the file xarray/tests/test_variable.py !

Comment last updated on December 07, 2018 at 09:40 Hours UTC

[dcherian]

Thanks @MBlaschek.

1. You'll need to also add a note to doc/whats-new.rst.
2. Looks like there's trailing whitespace in test_variable.py that will need to be fixed.

EDIT: Looks like the tests aren't running because of this ImportError

ImportError while importing test module '/home/travis/build/pydata/xarray/xarray/tests/test_variable.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
xarray/tests/test_variable.py:27: in <module>
    from . import (
E   ImportError: cannot import name 'set_options'

I think you need from xarray import set_options as in test_dataset.py. You can test this out locally using pytest. We have some documentation on contributing here: http://xarray.pydata.org/en/stable/contributing.html. Feel free to ask if you have questions

[MBlaschek]

I hope that is all you guys wanted. It's kinda complicated for me to follow all these procedures to do really simple thing. I hope that helps and thanks for the inside into pull-requests.
Please let me know if I can close it and be done with it.

[dcherian]

Thanks, @MBlaschek. Looks great to me.

[shoyer]

Thank @MBlaschek -- we appreciate your help here! It does get easier for next time, I promise :)

[MBlaschek]

Cool. I will keep using Xarray. Thanks for the great work