Change order of dims in example of make_xarray_grid

[santisoler]

Change the order of the dimensions of DataArrays in the examples of
make_xarray_grid, since xarray v0.19.0 prints them in a different order.
Tell pytest to ignore the outputs of the print statements in the
make_xarray_grid examples while running doctests.

Reminders:

• Run make format and make check to make sure the code follows the style guide.
• Add tests for new features or tests that would have caught the bug that you're fixing.
• Add new public functions/methods/classes to doc/api/index.rst and the base __init__.py file for the package.
• Write detailed docstrings for all functions/classes/methods. It often helps to design better code if you write the docstrings first.
• If adding new functionality, add an example to the docstring, gallery, and/or tutorials.
• Add your full name, affiliation, and ORCID (optional) to the AUTHORS.md file (if you haven't already) in case you'd like to be listed as an author on the Zenodo archive of the next release.

[santisoler]

@leouieda The xarray version that is changing the default behavior is 0.19.0, while on Python3.6 conda installs xarray 0.18.2.
Now we have a single example that prints different outputs depending on the version you are running. How can we tackle this?

[santisoler]

Should we tell pytest to skip running the print lines? https://docs.pytest.org/en/latest/how-to/doctest.html#skipping-tests

[leouieda]

My recommendation here is to change the test. I’ve been bitten by tests relying on reprs and they inevitably break. This happens even with numpy arrays, which are relatively stable. So the best thing to do is to check attributes, types, or print formatted values instead of relying on the repr.

[santisoler]

My recommendation here is to change the test. I’ve been bitten by tests relying on reprs and they inevitably break. This happens even with numpy arrays, which are relatively stable. So the best thing to do is to check attributes, types, or print formatted values instead of relying on the repr.

Ok. So the idea is to tell pytest to don't check the output of the print statement and possibly add a few other lines in the example showing the attributes of the generated output. Does it make sense?

[santisoler]

I think this should be enough. The tests for the make_xarray_grid are complete enough, so I think asking pytest to ignore those print statements on the examples is a good compromise. Let me know what do you think, and feel free to merge if you like it.

[leouieda]

My idea was more "don't use print in doctests" but this is better since the example is easier to read 👍