Bugfix empty entity lists (#15035)

* Bugfix empty entity lists

* Add tests

* Update test_entity_platform.py

* Update entity_platform.py

homeassistant/helpers/entity_platform.py

@@ -216,6 +216,10 @@ class EntityPlatform(object):
                                    component_entities, registry)
             for entity in new_entities]
 
+        # No entities for processing
+        if not tasks:
+            return
+
         await asyncio.wait(tasks, loop=self.hass.loop)
         self.async_entities_added_callback()
 

tests/helpers/test_entity_platform.py

@@ -592,3 +592,13 @@ async def test_reset_cancels_retry_setup(hass):
 
     assert len(mock_call_later.return_value.mock_calls) == 1
     assert ent_platform._async_cancel_retry_setup is None
+
+
+@asyncio.coroutine
+def test_not_fails_with_adding_empty_entities_(hass):
+    """Test for not fails on empty entities list."""
+    component = EntityComponent(_LOGGER, DOMAIN, hass)
+
+    yield from component.async_add_entities([])
+
+    assert len(hass.states.async_entity_ids()) == 0