Use transitionEnd in QUnit since we moved away from PhantomJS

js/src/util.js

@@ -14,8 +14,7 @@ const Util = (($) => {
    * ------------------------------------------------------------------------
    */
 
-  let transition = false
-
+  const TRANSITION_END = 'transitionend'
   const MAX_UID = 1000000
   const MILLISECONDS_MULTIPLIER = 1000
 
@@ -26,8 +25,8 @@ const Util = (($) => {
 
   function getSpecialTransitionEndEvent() {
     return {
-      bindType: transition.end,
-      delegateType: transition.end,
+      bindType: TRANSITION_END,
+      delegateType: TRANSITION_END,
       handle(event) {
         if ($(event.target).is(this)) {
           return event.handleObj.handler.apply(this, arguments) // eslint-disable-line prefer-rest-params
@@ -37,16 +36,6 @@ const Util = (($) => {
     }
   }
 
-  function transitionEndTest() {
-    if (typeof window !== 'undefined' && window.QUnit) {
-      return false
-    }
-
-    return {
-      end: 'transitionend'
-    }
-  }
-
   function transitionEndEmulator(duration) {
     let called = false
 
@@ -64,13 +53,8 @@ const Util = (($) => {
   }
 
   function setTransitionEndSupport() {
-    transition = transitionEndTest()
-
     $.fn.emulateTransitionEnd = transitionEndEmulator
-
-    if (Util.supportsTransitionEnd()) {
-      $.event.special[Util.TRANSITION_END] = getSpecialTransitionEndEvent()
-    }
+    $.event.special[Util.TRANSITION_END] = getSpecialTransitionEndEvent()
   }
 
   /**
@@ -130,11 +114,12 @@ const Util = (($) => {
     },
 
     triggerTransitionEnd(element) {
-      $(element).trigger(transition.end)
+      $(element).trigger(TRANSITION_END)
     },
 
+    // TODO: Remove in v5
     supportsTransitionEnd() {
-      return Boolean(transition)
+      return Boolean(TRANSITION_END)
     },
 
     isElement(obj) {