Add basic swarming UI tests

appengine/swarming/ui/build/elements.html

Index: appengine/swarming/ui/build/elements.html
diff --git a/appengine/swarming/ui/build/elements.html b/appengine/swarming/ui/build/elements.html
index 9f4d8a2a115aa05c49fb2664ac5c73566e67d6a8..8d55be23304ce7c9cfd606278b5004bd75280c0e 100644
--- a/appengine/swarming/ui/build/elements.html
+++ b/appengine/swarming/ui/build/elements.html
@@ -237,10 +237,14 @@ delete this[t])},_configureProperties:function(e,t){for(var n in e){var r=e[n];i
           }
           this.set("_cursor", json.cursor || END);
           this.set("busy", false);
+          // for unit testing
+          this.fire("_finishedLoading", {success:true});
         }.bind(this)).catch(function(reason){
           console.log("Reason for failure of request to " + this._url, reason);
           sk.errorMessage("Could not get next set of results. Try reloading the page?", 0);
           this.set("busy", false);
+          // for unit testing
+          this.fire("_finishedLoading", {success:true});
         }.bind(this));
       },