add sorted function to mockrealm objects

changeme/__mock__/mockRealmObject.js

@@ -17,6 +17,7 @@ export default class MockRealm{
   objects(repoName){
     let objects = this[repoName];
     objects.filtered = this.filtered ? this.filtered.bind(this, repoName) : () => objects;
+    objects.sorted = this.sorted ? this.sorted.bind(this, repoName) : () => objects;
     return objects;
   }