Cannot import xarray.tests due to use of pytest.config

xarray.tests cannot be imported due to the use of pytest.config:

$ python -c "import xarray; print(xarray.__version__); import xarray.tests"
0.9.2-3-g9479038
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/home/jhelmus/devel/xarray/xarray/tests/__init__.py", line 118, in <module>
    not pytest.config.getoption("--run-flaky"),
AttributeError: module 'pytest' has no attribute 'config'

The use of pytest.config in the xarray/tests/__init__.py seem to have been introduced in #1336. From the discussion in pytest-dev/pytest#1688 it seems as if the use of pytest.config is discouraged.

[jjhelmus]

Just out of curiosity, what reason did you have for importing xarray.tests?

xarray.tests is listed as a import test in the conda-forge xarray-feedstock and was failing when I was doing a build. I do not think that import line needs to be present, tests does not seem to be in the public API of xarray. I’d be in favor of removing that line and keeping the test suite setup as-is.

[jjhelmus]

@shoyer Agreed, there is no need for xarray.tests to be importable. Closing this issue, thanks for the quick clarification.