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
780726453,MDExOlB1bGxSZXF1ZXN0NTUwNTczNjM4,4773,CI: ignore some warnings,10194086,closed,0,,,2,2021-01-06T17:34:05Z,2021-01-07T21:00:31Z,2021-01-07T21:00:27Z,MEMBER,,0,pydata/xarray/pulls/4773,"<!-- Feel free to remove check-list items aren't relevant to your change -->

- [x] Part of #3266
- [x] Passes `isort . && black . && mypy . && flake8`

Supresses 3 warnings we get in the test suite. Two are trivial. The third is `PytestUnraisableExceptionWarning: Exception ignored in: CachingFileManager.__del__`:

- The test triggers an error is in `CachingFileManager.__init__`:

https://github.com/pydata/xarray/blob/31d540f9d668fc5f8c1c92165f950c568778db01/xarray/tests/test_backends_file_manager.py#L205-L207

- It then tries to run `__del__` but there is an error because an attribute is not available (as `__init__` failed)

https://github.com/pydata/xarray/blob/31d540f9d668fc5f8c1c92165f950c568778db01/xarray/backends/file_manager.py#L238

- However, errors in `__del__` are ignored, therefore we get a `PytestUnraisableExceptionWarning`

I decided to suppress the error and not fix  `CachingFileManager` as I think that's nothing user-facing...","{""url"": ""https://api.github.com/repos/pydata/xarray/issues/4773/reactions"", ""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,,13221727,pull