Add is_state_attr method.

Returns True if the entity exists and has an attribute with the given
name and value.

homeassistant/core.py

@@ -468,6 +468,13 @@ class StateMachine(object):
         return (entity_id in self._states and
                 self._states[entity_id].state == state)
 
+    def is_state_attr(self, entity_id, name, value):
+        """Test if entity exists and has a state attribute set to value."""
+        entity_id = entity_id.lower()
+
+        return (entity_id in self._states and
+                self._states[entity_id].attributes.get(name, None) == value)
+
     def remove(self, entity_id):
         """Remove the state of an entity.
 

homeassistant/util/template.py

@@ -43,7 +43,8 @@ def render(hass, template, variables=None, **kwargs):
     try:
         return ENV.from_string(template, {
             'states': AllStates(hass),
-            'is_state': hass.states.is_state
+            'is_state': hass.states.is_state,
+            'is_state_attr': hass.states.is_state_attr
         }).render(kwargs).strip()
     except jinja2.TemplateError as err:
         raise TemplateError(err)

tests/test_core.py

@@ -321,6 +321,18 @@ class TestStateMachine(unittest.TestCase):
         self.assertFalse(self.states.is_state('light.Bowl', 'off'))
         self.assertFalse(self.states.is_state('light.Non_existing', 'on'))
 
+    def test_is_state_attr(self):
+        """ Test is_state_attr method. """
+        self.states.set("light.Bowl", "on", {"brightness": 100})
+        self.assertTrue(
+            self.states.is_state_attr('light.Bowl', 'brightness', 100))
+        self.assertFalse(
+            self.states.is_state_attr('light.Bowl', 'friendly_name', 200))
+        self.assertFalse(
+            self.states.is_state_attr('light.Bowl', 'friendly_name', 'Bowl'))
+        self.assertFalse(
+            self.states.is_state_attr('light.Non_existing', 'brightness', 100))
+
     def test_entity_ids(self):
         """ Test get_entity_ids method. """
         ent_ids = self.states.entity_ids()

tests/util/test_template.py

@@ -117,6 +117,14 @@ class TestUtilTemplate(unittest.TestCase):
                 self.hass,
                 '{% if is_state("test.object", "available") %}yes{% else %}no{% endif %}'))
 
+    def test_is_state_attr(self):
+        self.hass.states.set('test.object', 'available', {'mode': 'on'})
+        self.assertEqual(
+            'yes',
+            template.render(
+                self.hass,
+                '{% if is_state_attr("test.object", "mode", "on") %}yes{% else %}no{% endif %}'))
+
     def test_states_function(self):
         self.hass.states.set('test.object', 'available')
         self.assertEqual(