diff --git a/databricks/koalas/tests/test_dataframe.py b/databricks/koalas/tests/test_dataframe.py
index fef22e432f..9bca990fe1 100644
--- a/databricks/koalas/tests/test_dataframe.py
+++ b/databricks/koalas/tests/test_dataframe.py
@@ -1373,6 +1373,9 @@ def test_all(self):
 
         self.assert_eq(kdf.all(), pdf.all())
 
+        with self.assertRaisesRegex(ValueError, 'axis should be either 0 or "index" currently.'):
+            kdf.all(axis=1)
+
     def test_any(self):
         pdf = pd.DataFrame({
             'col1': [False, False, False],
@@ -1398,6 +1401,9 @@ def test_any(self):
 
         self.assert_eq(kdf.any(), pdf.any())
 
+        with self.assertRaisesRegex(ValueError, 'axis should be either 0 or "index" currently.'):
+            kdf.any(axis=1)
+
     def test_rank(self):
         pdf = pd.DataFrame(data={'col1': [1, 2, 3, 1], 'col2': [3, 4, 3, 1]},
                            columns=['col1', 'col2'])
diff --git a/databricks/koalas/tests/test_series.py b/databricks/koalas/tests/test_series.py
index d56269ea00..6958cc40fb 100644
--- a/databricks/koalas/tests/test_series.py
+++ b/databricks/koalas/tests/test_series.py
@@ -621,3 +621,9 @@ def test_shift(self):
                              repr(pser.shift(periods=2, fill_value=0)))
         with self.assertRaisesRegex(ValueError, 'periods should be an int; however'):
             kser.shift(periods=1.5)
+
+    def test_astype(self):
+        pser = pd.Series([10, 20, 15, 30, 45], name='x')
+        kser = koalas.Series(pser)
+        with self.assertRaisesRegex(ValueError, 'Type int63 not understood'):
+            kser.astype('int63')
diff --git a/databricks/koalas/tests/test_series_datetime.py b/databricks/koalas/tests/test_series_datetime.py
index 9a5e322728..72aebc4c32 100644
--- a/databricks/koalas/tests/test_series_datetime.py
+++ b/databricks/koalas/tests/test_series_datetime.py
@@ -57,6 +57,13 @@ def test_subtraction(self):
 
         self.assertEqual(list(kdf['diff_seconds'].toPandas()), [35545499, 33644699, 31571099])
 
+        kdf = ks.from_pandas(pd.DataFrame({
+                                          'a': pd.date_range('2016-12-31', '2017-01-08', freq='D'),
+                                          'b': pd.Series(range(9))}))
+        expected_error_message = 'datetime subtraction can only be applied to datetime series.'
+        with self.assertRaisesRegex(TypeError, expected_error_message):
+            kdf['a'] - kdf['b']
+
     @unittest.skip(
         "It fails in certain OSs presumably due to different "
         "timezone behaviours inherited from C library.")