Raise NotImplementedError when attempting to use a pandas.MultiIndex

Related: pydata#164

Author: shoyer

test/test_data_array.py

@@ -198,6 +198,10 @@ def test_constructor_from_self_described(self):
         actual = DataArray(Coordinate('foo', ['a', 'b']))
         self.assertDataArrayIdentical(expected, actual)
 
+        s = pd.Series(range(2), pd.MultiIndex.from_product([['a', 'b'], [0]]))
+        with self.assertRaisesRegexp(NotImplementedError, 'MultiIndex'):
+            DataArray(s)
+
     def test_equals_and_identical(self):
         da2 = self.dv.copy()
         self.assertTrue(self.dv.equals(da2))

xray/variable.py

@@ -718,6 +718,11 @@ class Coordinate(Variable):
     _cache_data_class = PandasIndexAdapter
 
     def __init__(self, name, data, attributes=None, encoding=None):
+        if isinstance(data, pd.MultiIndex):
+            raise NotImplementedError(
+                'no support yet for using a pandas.MultiIndex in an '
+                'xray.Coordinate')
+
         super(Coordinate, self).__init__(name, data, attributes, encoding)
         if self.ndim != 1:
             raise ValueError('%s objects must be 1-dimensional' %