Add test with xgcm

ci/environment.yml

@@ -10,6 +10,7 @@ dependencies:
   - pytest-cov
   - pytest-sugar
   - xarray>=0.18,!=0.20.0,!=0.20.1
+  - xgcm
   - pooch
   - pip:
       - -r ../requirements.txt

tests/test_postprocess.py

@@ -3,6 +3,8 @@
 
 import xwrf
 
+from . import importorskip
+
 
 @pytest.fixture(scope='session', params=['dummy'])
 def dummy_dataset(request):
@@ -14,6 +16,11 @@ def dummy_attrs_only_dataset(request):
     return xwrf.tutorial.open_dataset(request.param)
 
 
+@pytest.fixture(scope='session')
+def test_grid(request):
+    return xwrf.tutorial.open_dataset(request.param)
+
+
 @pytest.mark.parametrize('variable', ('Q2', 'PSFC'))
 def test_cf_attrs_added(dummy_dataset, variable):
     dataset = xwrf.postprocess._modify_attrs_to_cf(dummy_dataset)
@@ -36,6 +43,20 @@ def test_include_projection_coordinates(dummy_dataset):
     assert dataset['Q2'].attrs['grid_mapping'] == 'wrf_projection'
 
 
+@importorskip('xgcm')
+@pytest.mark.parametrize('test_grid', ['lambert_conformal', 'mercator'], indirect=True)
+def test_include_projection_coordinates_with_xgcm(test_grid):
+    from xgcm import Grid
+
+    dataset = xwrf.postprocess._include_projection_coordinates(test_grid)
+    grid = Grid(dataset)
+
+    assert grid.axes['Y'].coords['center'] == 'south_north'
+    assert grid.axes['Y'].coords['outer'] == 'south_north_stag'
+    assert grid.axes['X'].coords['center'] == 'west_east'
+    assert grid.axes['X'].coords['outer'] == 'west_east_stag'
+
+
 def test_warning_on_projection_coordinate_failure(dummy_attrs_only_dataset):
     with pytest.warns(UserWarning):
         dataset = xwrf.postprocess._include_projection_coordinates(dummy_attrs_only_dataset)