add commit number to test

Author: jreback

pandas/tests/indexes/test_multi.py

@@ -1721,6 +1721,7 @@ def test_from_tuples(self):
         assert len(idx) == 2
 
     def test_from_tuples_empty(self):
+        # GH 16777
         result = MultiIndex.from_tuples([], names=['a', 'b'])
         expected = MultiIndex.from_arrays(arrays=[[], []],
                                           names=['a', 'b'])