diff --git a/test/test_component_group.py b/test/test_component_group.py
index 1b039358e03..a5b4c0eb60a 100644
--- a/test/test_component_group.py
+++ b/test/test_component_group.py
@@ -21,10 +21,14 @@ class TestComponentsGroup(unittest.TestCase):
 
         self.hass.states.set('light.Bowl', comps.STATE_ON)
         self.hass.states.set('light.Ceiling', comps.STATE_OFF)
+        self.hass.states.set('switch.AC', comps.STATE_OFF)
         group.setup_group(self.hass, 'init_group',
                           ['light.Bowl', 'light.Ceiling'], False)
+        group.setup_group(self.hass, 'mixed_group',
+                          ['light.Bowl', 'switch.AC'], False)
 
         self.group_name = group.ENTITY_ID_FORMAT.format('init_group')
+        self.mixed_group_name = group.ENTITY_ID_FORMAT.format('mixed_group')
 
     def tearDown(self):  # pylint: disable=invalid-name
         """ Stop down stuff we started. """
@@ -56,6 +60,26 @@ class TestComponentsGroup(unittest.TestCase):
         group_state = self.hass.states.get(self.group_name)
         self.assertEqual(comps.STATE_ON, group_state.state)
 
+        # Try to setup a group with mixed groupable states
+        self.hass.states.set('device_tracker.Paulus', comps.STATE_HOME)
+        self.assertFalse(group.setup_group(
+            self.hass, 'person_and_light',
+            ['light.Bowl', 'device_tracker.Paulus']))
+
+        # Try to setup a group with a non existing state
+        self.assertNotIn('non.existing', self.hass.states.entity_ids)
+        self.assertFalse(group.setup_group(
+            self.hass, 'light_and_nothing',
+            ['light.Bowl', 'non.existing']))
+
+        # Try to setup a group with non groupable states
+        self.hass.states.set('cast.living_room', "Plex")
+        self.hass.states.set('cast.bedroom', "Netflix")
+        self.assertFalse(
+            group.setup_group(
+                self.hass, 'chromecasts',
+                ['cast.living_room', 'cast.bedroom']))
+
     def test__get_group_type(self):
         """ Test _get_group_type method. """
         self.assertEqual('on_off', group._get_group_type(comps.STATE_ON))
@@ -65,6 +89,9 @@ class TestComponentsGroup(unittest.TestCase):
         self.assertEqual('home_not_home',
                          group._get_group_type(comps.STATE_NOT_HOME))
 
+        # Unsupported state
+        self.assertIsNone(group._get_group_type('unsupported_state'))
+
     def test_is_on(self):
         """ Test is_on method. """
         self.assertTrue(group.is_on(self.hass, self.group_name))
@@ -72,23 +99,43 @@ class TestComponentsGroup(unittest.TestCase):
         self.hass._pool.block_till_done()
         self.assertFalse(group.is_on(self.hass, self.group_name))
 
+        # Try on non existing state
+        self.assertFalse(group.is_on(self.hass, 'non.existing'))
+
     def test_expand_entity_ids(self):
         """ Test expand_entity_ids method. """
         self.assertEqual(sorted(['light.Ceiling', 'light.Bowl']),
                          sorted(group.expand_entity_ids(
                              self.hass, [self.group_name])))
 
+        # Make sure that no duplicates are returned
         self.assertEqual(
             sorted(['light.Ceiling', 'light.Bowl']),
             sorted(group.expand_entity_ids(
                 self.hass, [self.group_name, 'light.Ceiling'])))
 
+        # Test that non strings are ignored
+        self.assertEqual([], group.expand_entity_ids(self.hass, [5, True]))
+
     def test_get_entity_ids(self):
         """ Test get_entity_ids method. """
+        # Get entity IDs from our group
         self.assertEqual(
             sorted(['light.Ceiling', 'light.Bowl']),
             sorted(group.get_entity_ids(self.hass, self.group_name)))
 
+        # Test domain_filter
+        self.assertEqual(
+            ['switch.AC'],
+            group.get_entity_ids(
+                self.hass, self.mixed_group_name, domain_filter="switch"))
+
+        # Test with non existing group name
+        self.assertEqual([], group.get_entity_ids(self.hass, 'non_existing'))
+
+        # Test with non-group state
+        self.assertEqual([], group.get_entity_ids(self.hass, 'switch.AC'))
+
     def test_setup(self):
         """ Test setup method. """
         self.assertTrue(