Update tests to include empty maps and NaT values

Author: nateyoder

Diff for: pandas/tests/indexes/datetimes/test_datetimelike.py

@@ -74,3 +74,29 @@ def test_union(self):
         for case in cases:
             result = first.union(case)
             self.assertTrue(tm.equalContents(result, everything))
+
+    def test_map(self):
+        expected = self.index + 1
+        tm.assert_index_equal(self.index.map(lambda x: x + 1), expected)
+
+        series_map = pd.Series(expected, self.index)
+        tm.assert_index_equal(self.index.map(series_map), expected)
+
+        dict_map = {i: e for e, i in zip(expected, self.index)}
+        tm.assert_index_equal(self.index.map(dict_map), expected)
+
+        # empty mappable
+        nan_index = Index([pd.np.nan] * len(self.index))
+        series_map = pd.Series()
+        tm.assert_index_equal(self.index.map(series_map), nan_index)
+        dict_map = {}
+        tm.assert_index_equal(self.index.map(dict_map), nan_index)
+
+        # map to NaT
+        result = self.index.map(lambda x: pd.NaT if x == self.index[0] else x)
+        expected = Index([pd.NaT] + self.index[1:].tolist())
+        tm.assert_index_equal(result, expected)
+        series_map = pd.Series(expected, self.index)
+        tm.assert_index_equal(self.index.map(series_map), expected)
+        dict_map = {i: e for e, i in zip(expected, self.index)}
+        tm.assert_index_equal(self.index.map(dict_map), expected)

Diff for: pandas/tests/indexes/period/test_period.py

@@ -765,12 +765,8 @@ def test_pickle_freq(self):
         self.assertEqual(new_prng.freq, offsets.MonthEnd())
         self.assertEqual(new_prng.freqstr, 'M')
 
-    def test_map(self):
+    def test_map_with_ordinal(self):
         index = PeriodIndex([2005, 2007, 2009], freq='A')
-        result = index.map(lambda x: x + 1)
-        expected = index + 1
-        tm.assert_index_equal(result, expected)
-
         result = index.map(lambda x: x.ordinal)
         exp = Index([x.ordinal for x in index])
         tm.assert_index_equal(result, exp)