Compute state display tests (#643)

* Move computeDomain and format functions to js

* Add tests for computeStateDisplay

* Always recalculate state display

* Remove LANGUAGE from hassUtils object

* Move AppLocalizeBehavior import to mixins

* Import mixins to state-card-display

* Safety check on computeStateDisplay

* Don't store computed domains on stateObj

* Integration tests for state-card-display

* Include extractDomain code in polymer repo

* Remove util function null checking

* Dont render test element without hass and stateObj

* Revert "Don't store computed domains on stateObj"

This reverts commit e3509d71823ff5e42a4dcf4849a98c5bb6cb391c.

* Revert "Always recalculate state display"

This reverts commit 27c24e2694ee6f7c147782532268b3a67998d49b.

js/common/util/compute_domain.js

@@ -0,0 +1,7 @@
+export default function computeDomain(stateObj) {
+  if (!stateObj._domain) {
+    stateObj._domain = stateObj.entity_id.substr(0, stateObj.entity_id.indexOf('.'));
+  }
+
+  return stateObj._domain;
+}