diff --git a/pandas/tests/indexes/datetimes/test_astype.py b/pandas/tests/indexes/datetimes/test_astype.py
index 4b989eb35e900..8acdd301f241a 100644
--- a/pandas/tests/indexes/datetimes/test_astype.py
+++ b/pandas/tests/indexes/datetimes/test_astype.py
@@ -138,6 +138,30 @@ def test_astype_object(self):
         tm.assert_index_equal(casted, Index(exp_values, dtype=np.object_))
         assert casted.tolist() == exp_values
 
+    @pytest.mark.parametrize('tz', [None, 'Asia/Tokyo'])
+    def test_astype_object_tz(self, tz):
+        idx = pd.date_range(start='2013-01-01', periods=4, freq='M',
+                            name='idx', tz=tz)
+        expected_list = [Timestamp('2013-01-31', tz=tz),
+                         Timestamp('2013-02-28', tz=tz),
+                         Timestamp('2013-03-31', tz=tz),
+                         Timestamp('2013-04-30', tz=tz)]
+        expected = pd.Index(expected_list, dtype=object, name='idx')
+        result = idx.astype(object)
+        tm.assert_index_equal(result, expected)
+        assert idx.tolist() == expected_list
+
+    def test_astype_object_with_nat(self):
+        idx = DatetimeIndex([datetime(2013, 1, 1), datetime(2013, 1, 2),
+                             pd.NaT, datetime(2013, 1, 4)], name='idx')
+        expected_list = [Timestamp('2013-01-01'),
+                         Timestamp('2013-01-02'), pd.NaT,
+                         Timestamp('2013-01-04')]
+        expected = pd.Index(expected_list, dtype=object, name='idx')
+        result = idx.astype(object)
+        tm.assert_index_equal(result, expected)
+        assert idx.tolist() == expected_list
+
     @pytest.mark.parametrize('dtype', [
         float, 'timedelta64', 'timedelta64[ns]', 'datetime64',
         'datetime64[D]'])
diff --git a/pandas/tests/indexes/datetimes/test_ops.py b/pandas/tests/indexes/datetimes/test_ops.py
index 4f386eb28cc0f..a0cc565564f35 100644
--- a/pandas/tests/indexes/datetimes/test_ops.py
+++ b/pandas/tests/indexes/datetimes/test_ops.py
@@ -51,49 +51,6 @@ def test_ops_properties_basic(self):
         assert s.day == 10
         pytest.raises(AttributeError, lambda: s.weekday)
 
-    def test_astype_object(self):
-        idx = pd.date_range(start='2013-01-01', periods=4, freq='M',
-                            name='idx')
-        expected_list = [Timestamp('2013-01-31'),
-                         Timestamp('2013-02-28'),
-                         Timestamp('2013-03-31'),
-                         Timestamp('2013-04-30')]
-        expected = pd.Index(expected_list, dtype=object, name='idx')
-        result = idx.astype(object)
-        assert isinstance(result, Index)
-
-        assert result.dtype == object
-        tm.assert_index_equal(result, expected)
-        assert result.name == expected.name
-        assert idx.tolist() == expected_list
-
-        idx = pd.date_range(start='2013-01-01', periods=4, freq='M',
-                            name='idx', tz='Asia/Tokyo')
-        expected_list = [Timestamp('2013-01-31', tz='Asia/Tokyo'),
-                         Timestamp('2013-02-28', tz='Asia/Tokyo'),
-                         Timestamp('2013-03-31', tz='Asia/Tokyo'),
-                         Timestamp('2013-04-30', tz='Asia/Tokyo')]
-        expected = pd.Index(expected_list, dtype=object, name='idx')
-        result = idx.astype(object)
-        assert isinstance(result, Index)
-        assert result.dtype == object
-        tm.assert_index_equal(result, expected)
-        assert result.name == expected.name
-        assert idx.tolist() == expected_list
-
-        idx = DatetimeIndex([datetime(2013, 1, 1), datetime(2013, 1, 2),
-                             pd.NaT, datetime(2013, 1, 4)], name='idx')
-        expected_list = [Timestamp('2013-01-01'),
-                         Timestamp('2013-01-02'), pd.NaT,
-                         Timestamp('2013-01-04')]
-        expected = pd.Index(expected_list, dtype=object, name='idx')
-        result = idx.astype(object)
-        assert isinstance(result, Index)
-        assert result.dtype == object
-        tm.assert_index_equal(result, expected)
-        assert result.name == expected.name
-        assert idx.tolist() == expected_list
-
     def test_minmax(self):
         for tz in self.tz:
             # monotonic