Added test for invalid input

Test exceptions in from_tuples/from_arrays/from_product

Author: Xbar

pandas/tests/indexes/test_multi.py

@@ -672,10 +672,16 @@ def test_from_arrays(self):
         for lev, lab in zip(self.index.levels, self.index.labels):
             arrays.append(np.asarray(lev).take(lab))
 
+        # list of arrays as input
         result = MultiIndex.from_arrays(arrays)
         assert list(result) == list(self.index)
-        result2 = MultiIndex.from_arrays(iter(arrays))  # iterator as input
+        # iterator as input
+        result2 = MultiIndex.from_arrays(iter(arrays))
         assert list(result2) == list(self.index)
+        # invlide iterator input
+        with tm.assert_raises_regex(
+                TypeError, "Inappropriate input for list of arrays."):
+            MultiIndex.from_arrays(0)
 
         # infer correctly
         result = MultiIndex.from_arrays([[pd.NaT, Timestamp('20130101')],
@@ -833,6 +839,10 @@ def test_from_product(self):
         result2 = MultiIndex.from_product(iter([first, second]), names=names)
         assert result2.equals(expected)
         assert result2.names == names
+        # Invalid non-iterable input
+        with tm.assert_raises_regex(TypeError,
+                                    "Inappropriate input for iterables."):
+            MultiIndex.from_product(0)
 
     def test_from_product_empty(self):
         # 0 levels
@@ -1735,12 +1745,18 @@ def test_from_tuples(self):
         expected = MultiIndex(levels=[[1, 3], [2, 4]],
                               labels=[[0, 1], [0, 1]],
                               names=['a', 'b'])
+        # input tuples
         res1 = MultiIndex.from_tuples(((1, 2), (3, 4)), names=['a', 'b'])
         assert expected.names == res1.names
         assert res1.equals(expected)
+        # input iterator for tuples
         res2 = MultiIndex.from_tuples(zip([1, 3], [2, 4]), names=['a', 'b'])
         assert expected.names == res2.names
         assert res2.equals(expected)
+        # input non-iterables
+        with tm.assert_raises_regex(TypeError,
+                                    'Inappropriate input for tuples.'):
+            MultiIndex.from_tuples(0)
 
     def test_from_tuples_empty(self):
         # GH 16777