config_service: fix testing

appengine/config_service/ui/src/config-ui/front-page.html

 <!--
   Copyright 2017 The LUCI Authors. All rights reserved.
   Use of this source code is governed under the Apache License, Version 2.0
   that can be found in the LICENSE file.
 -->
 
 <link rel="import" href="../../bower_components/app-layout/app-layout.html">
 <link rel="import" href="../../bower_components/iron-ajax/iron-ajax.html">
 <link rel="import" href="../../bower_components/paper-button/paper-button.html">
 <link rel="import" href="../../bower_components/paper-search/paper-search-bar.html">
@@ skipping 127 matching lines @@
       },
 
       _isEmpty: function(array) {
         return array.length === 0;
       },
 
       _onGotConfigSets: function(event) {
         this.configSetList = event.detail.response.config_sets;
         this._updateSearchResults();
         this.isLoading = false;
+        this.fire('processedConfigSets');
       },
 
       _not: function(b) {
         return !b;
       },
 
       _updateSearchResults: function() {
         // This method sorts search results by the name of the config set, that way
         // the list doesn't consist of all projects followed by all services due to
         // the path beginning with "projects/" or "services/"
         var tempResults = this.configSetList.filter(e => e.config_set.includes(this.query));
         tempResults.sort(function(a, b) {
           return this._formatName(a.config_set).localeCompare(this._formatName(b.config_set));
         }.bind(this));
         this.searchResults = tempResults;
       },
 
     });
   </script>
 </dom-module>