TST: tests for inconsistent indexing with datetimes (pandas-dev#20550)

Author: jcontesti

pandas/tests/frame/test_indexing.py

@@ -1550,6 +1550,25 @@ def test_setitem_single_column_mixed_datetime(self):
         # pytest.raises(
         #    Exception, df.loc.__setitem__, ('d', 'timestamp'), [nan])
 
+    def test_setitem_mixed_datetime(self):
+        # GH 9336
+        expected = DataFrame({'a': [0, 0, 0, 0, 13, 14],
+                              'b': [pd.datetime(2012, 1, 1),
+                                    1,
+                                    'x',
+                                    'y',
+                                    pd.datetime(2013, 1, 1),
+                                    pd.datetime(2014, 1, 1)]})
+        df = pd.DataFrame(0, columns=list('ab'), index=range(6))
+        df['b'] = pd.NaT
+        df.loc[0, 'b'] = pd.datetime(2012, 1, 1)
+        df.loc[1, 'b'] = 1
+        df.loc[[2, 3], 'b'] = 'x', 'y'
+        A = np.array([[13, np.datetime64('2013-01-01T00:00:00')],
+                      [14, np.datetime64('2014-01-01T00:00:00')]])
+        df.loc[[4, 5], ['a', 'b']] = A
+        assert_frame_equal(df, expected)
+
     def test_setitem_frame(self):
         piece = self.frame.loc[self.frame.index[:2], ['A', 'B']]
         self.frame.loc[self.frame.index[-2]:, ['A', 'B']] = piece.values