issues: 571743567

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id node_id number title user state locked assignee milestone comments created_at updated_at closed_at author_association active_lock_reason draft pull_request body reactions performed_via_github_app state_reason repo type
571743567 MDExOlB1bGxSZXF1ZXN0MzgwNTc1NTYw 3801 Coarsen keep attrs 3376 29958771 closed 0     19 2020-02-27T00:29:13Z 2020-03-06T16:33:11Z 2020-03-02T23:02:56Z CONTRIBUTOR   0 pydata/xarray/pulls/3801
  • [x] Closes #3376
  • [x] Tests added
  • [x] Passes isort -rc . && black . && mypy . && flake8
  • [x] Fully documented, including whats-new.rst for all changes and api.rst for new API

I also noticed missing attributes when attempting certain operations, so I have created this pull request to attempt a fix. I modified code in DataWithCoords.coarsen() to try applying the same logic used for other methods since #2482 was successfully merged.

I added two new tests that adapt the bug reported by @jejjohnson. I believe they should pass when this is fixed. One uses Dataset.coarsen() and the other uses Variable.coarsen. Both tests currently fail.

xarray/tests/test_dataset.py::TestDataset::test_coarsen_keep_attrs - fails because my attempted fix does not retain the attributes.

xarray/tests/test_variable.py::TestVariable::test_coarsen_keep_attrs - also fails, but unexpectedly this seems to be because the attributes are not removed by default, or even when explicitly setting the global option to False. 

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