Method required to compare xarray datasets / coordinates incl. metadata

[sol1105]

• clisops version: dev

Description

Need to implement a comparison between xarray datasets to compare the grids and metadata.
This is required

• to be able to identify applicable weight files in the (yet to be implemented) cache
• to be able to set up tests that assert that the desired output grid has been generated / remapped to

[agstephens]

@sol1105, here are some possible solutions for us to test out:

• http://xarray.pydata.org/en/stable/generated/xarray.Dataset.equals.html
• http://xarray.pydata.org/en/stable/generated/xarray.testing.assert_equal.html
• http://xarray.pydata.org/en/stable/generated/xarray.testing.assert_identical.html
• http://xarray.pydata.org/en/stable/generated/xarray.testing.assert_allclose.html
• http://xarray.pydata.org/en/stable/generated/xarray.DataArray.equals.html
• http://xarray.pydata.org/en/stable/generated/xarray.DataArray.identical.html

We might not need to write any extra code.

If we have a situation where we need to do a partial comparison, we can probably do:

assert isinstance(da1, xr.DataArray) 
assert isinstance(da2, xr.DataArray)

da1_part = da1.drop(...stuff we don't want to compare...)
da2_part = da2.drop(...stuff we don't want to compare...)

xr.testing.assert_identical(da1_part, da2_part)