Minor cleanups

1. Avoid _describe and use pytest's capsys fixture to test stdout text
2. Avoid unnecessarily specifying default to mappers

Author: dcherian

cf_xarray/accessor.py

@@ -139,6 +139,9 @@ def wrapper(
             error: bool = True,
             default: str = None,
         ) -> List[Optional[str]]:
+            """
+            This decorator will add `error` and `default` kwargs to the decorated Mapper function.
+            """
             if key not in valid_keys:
                 if error:
                     raise KeyError(
@@ -645,21 +648,26 @@ def __getattr__(self, attr):
     def plot(self):
         return _CFWrappedPlotMethods(self._obj, self)
 
-    def _describe(self):
+    def describe(self):
+        """
+        Print a string repr to screen.
+        """
         text = "Axes:\n"
         for key in _AXIS_NAMES:
-            text += f"\t{key}: {_get_axis_coord(self._obj, key, error=False, default=None)}\n"
+            text += f"\t{key}: {_get_axis_coord(self._obj, key, error=False)}\n"
 
         text += "\nCoordinates:\n"
         for key in _COORD_NAMES:
-            text += f"\t{key}: {_get_axis_coord(self._obj, key, error=False, default=None)}\n"
+            text += f"\t{key}: {_get_axis_coord(self._obj, key, error=False)}\n"
 
         text += "\nCell Measures:\n"
         for measure in _CELL_MEASURES:
             if isinstance(self._obj, xr.Dataset):
                 text += f"\t{measure}: unsupported\n"
             else:
-                text += f"\t{measure}: {_get_measure(self._obj, measure, error=False, default=None)}\n"
+                text += (
+                    f"\t{measure}: {_get_measure(self._obj, measure, error=False)}\n"
+                )
 
         text += "\nStandard Names:\n"
         if isinstance(self._obj, xr.DataArray):
@@ -670,13 +678,7 @@ def _describe(self):
             text += "\n".join(
                 textwrap.wrap(f"{stdnames!r}", 70, break_long_words=False)
             )
-        return text
-
-    def describe(self):
-        """
-        Print a string repr to screen.
-        """
-        print(self._describe())
+        print(text)
 
     def get_valid_keys(self) -> Set[str]:
         """

cf_xarray/tests/test_accessor.py

@@ -51,14 +51,15 @@ def test_dicts():
     assert actual == expected
 
 
-def test_describe():
-    actual = airds.cf._describe()
+def test_describe(capsys):
+    airds.cf.describe()
+    actual = capsys.readouterr().out
     expected = (
         "Axes:\n\tX: ['lon']\n\tY: ['lat']\n\tZ: [None]\n\tT: ['time']\n"
         "\nCoordinates:\n\tlongitude: ['lon']\n\tlatitude: ['lat']"
         "\n\tvertical: [None]\n\ttime: ['time']\n"
         "\nCell Measures:\n\tarea: unsupported\n\tvolume: unsupported\n"
-        "\nStandard Names:\n\t['air_temperature', 'latitude', 'longitude', 'time']"
+        "\nStandard Names:\n\t['air_temperature', 'latitude', 'longitude', 'time']\n"
     )
     assert actual == expected