Use classList API

spec/controlbox.js

@@ -115,15 +115,15 @@
                         });
                         _converse.rosterview.update(); // XXX: Will normally called as event handler
                     }
-                    test_utils.waitUntil(function () {
+                    return test_utils.waitUntil(function () {
                         if (_converse.rosterview.$roster.hasScrollBar()) {
                             return $filter.is(':visible');
                         } else {
                             return !$filter.is(':visible');
                         }
-                    }).then(function () {
-                        done();
-                    });
+                }).then(function () {
+                    done();
+                });
                 });
             }));
 

src/converse-rosterview.js

@@ -166,12 +166,12 @@
                 },
 
                 renderClearButton: function () {
-                    var $roster_filter = this.$('.roster-filter');
-                    $roster_filter[this.tog($roster_filter.val())]('x');
+                    var roster_filter = this.el.querySelector('.roster-filter');
+                    roster_filter.classList[this.tog(roster_filter.value)]('x');
                 },
 
                 tog: function (v) {
-                    return v?'addClass':'removeClass';
+                    return v?'add':'remove';
                 },
 
                 toggleX: function (ev) {