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 e3509d7182.

* Revert "Always recalculate state display"

This reverts commit 27c24e2694.

js/common/util/format_date_time.js

@@ -0,0 +1,22 @@
+// Check for support of native locale string options
+function toLocaleStringSupportsOptions() {
+  try {
+    new Date().toLocaleString('i');
+  } catch (e) {
+    return e.name === 'RangeError';
+  }
+  return false;
+}
+
+export default (toLocaleStringSupportsOptions() ?
+  function (dateObj, locales) {
+    return dateObj.toLocaleString(locales, {
+      year: 'numeric',
+      month: 'long',
+      day: 'numeric',
+      hour: 'numeric',
+      minute: '2-digit',
+    });
+  } : function (dateObj, locales) { // eslint-disable-line no-unused-vars
+    return window.fecha.format(dateObj, 'haDateTime');
+  });