Fix cell measures parser (#112)

* break tests

* fix cell_measures parser

Author: malmans2

cf_xarray/accessor.py

@@ -367,7 +367,7 @@ def _get_measure(da: Union[DataArray, Dataset], key: str) -> List[str]:
         )
 
     attr = da.attrs["cell_measures"]
-    strings = [s.strip() for s in attr.strip().split(":")]
+    strings = [s for scolons in attr.split(":") for s in scolons.split()]
     if len(strings) % 2 != 0:
         raise ValueError(f"attrs['cell_measures'] = {attr!r} is malformed.")
     measures = dict(zip(strings[slice(0, None, 2)], strings[slice(1, None, 2)]))

cf_xarray/tests/test_accessor.py

@@ -53,8 +53,10 @@ def test_coordinates():
 
 
 def test_cell_measures():
+    da = airds["air"].copy()
+    da.attrs["cell_measures"] += " dummy: dummy"
     expected = dict(area=["cell_area"])
-    actual = airds["air"].cf.cell_measures
+    actual = da.cf.cell_measures
     assert actual == expected
 
     with pytest.raises(AssertionError, match=r"this only works with DataArrays"):