Got more tests working. Support for elllipsis

Author: dcherian

cf_xarray/accessor.py

@@ -14,6 +14,9 @@
 )
 
 
+_DEFAULT_KEYS_TO_REWRITE = ("dim", "coord", "group")
+
+
 def _get_axis_name_mapping(da: xr.DataArray):
     return {"X": "lon", "Y": "lat", "T": "time"}
 
@@ -23,7 +26,7 @@ def _getattr(
     attr: str,
     accessor: "CFAccessor",
     wrap_classes=False,
-    keys=("dim",),
+    keys=_DEFAULT_KEYS_TO_REWRITE,
 ):
     """
     Common getattr functionality.
@@ -142,6 +145,8 @@ def _rewrite_values_with_axis_names(self, kwargs, keys, var_kws):
                 if isinstance(value, dict):
                     # this for things like isel where **kwargs captures things like T=5
                     updates[key] = {self._coords.get(k, k): v for k, v in value.items()}
+                elif value is Ellipsis:
+                    pass
                 else:
                     # things like sum which have dim
                     updates[key] = [self._coords.get(v, v) for v in value]

cf_xarray/tests/test_accessor.py

@@ -22,25 +22,43 @@
         ("resample", {"time": "M"}, {"T": "M"}),
         ("rolling", {"lat": 5}, {"Y": 5}),
         ("coarsen", {"lon": 2, "lat": 5}, {"X": 2, "Y": 5}),
-        # groupby
+        ("groupby", {"group": "time"}, {"group": "T"})
+        # groupby("time.day")?
         # groupby_bins
         # weighted
     ),
 )
 def test_wrapped_classes(obj, attr, xrkwargs, cfkwargs):
+
+    if attr in ("rolling", "coarsen"):
+        # TODO: xarray bug, rolling and coarsen don't accept ellipsis
+        args = ()
+    else:
+        args = (...,)
+
     with raise_if_dask_computes():
-        expected = getattr(obj, attr)(**xrkwargs).mean()
-        actual = getattr(obj.cf, attr)(**cfkwargs).mean()
+        expected = getattr(obj, attr)(**xrkwargs).mean(*args)
+        actual = getattr(obj.cf, attr)(**cfkwargs).mean(*args)
     assert_identical(expected, actual)
 
+    if attr in ("groupby", "groupby_bins"):
+        # TODO: this should work for resample too?
+        with raise_if_dask_computes():
+            expected = getattr(obj, attr)(**xrkwargs).mean("lat")
+            actual = getattr(obj.cf, attr)(**cfkwargs).mean("Y")
+        assert_identical(expected, actual)
+
 
 @pytest.mark.parametrize("obj", objects)
-def test_other_methods(obj):
+def test_kwargs_methods(obj):
     with raise_if_dask_computes():
         expected = obj.isel(time=slice(2))
         actual = obj.cf.isel(T=slice(2))
     assert_identical(expected, actual)
 
+
+@pytest.mark.parametrize("obj", objects)
+def test_args_methods(obj):
     with raise_if_dask_computes():
         expected = obj.sum("time")
         actual = obj.cf.sum("T")