Spinner: Prevent double mousewheel & wheel event handling

As of gh-2338, if one has loaded the jQuery MouseWheel plugin, the `mousewheel`
handler would fire the `wheel` one, but the `wheel` one would also run in
response to the native `wheel` event, resulting in double the distance handled
by the spinner. To prevent the issue, only fire the `wheel` handler from inside
the `mousewheel` on if the event was triggered by jQuery - jQuery will not care
that the underlying event is `wheel` and will only fire handlers for
`mousewheel`.

Also, add an iframe test using jQuery MouseWheel to not affect all the other
tests.

Plus, migrate from `QUnit.reset` to `QUnit.done` (see qunitjs/qunit#354).

Closes gh-2342
Ref gh-2338

1 files changed, 7 insertions, 0 deletions

diff --git a/ui/widgets/spinner.js b/ui/widgets/spinner.js
index 4fb41d7bb..d4034b458 100644
--- a/ui/widgets/spinner.js
+++ b/ui/widgets/spinner.js
@@ -164,6 +164,13 @@ $.widget( "ui.spinner", {
 		// event. The `delta` parameter is provided by the jQuery Mousewheel
 		// plugin if one is loaded.
 		mousewheel: function( event, delta ) {
+			if ( !event.isTrigger ) {
+
+				// If this is not a trigger call, the `wheel` handler will
+				// fire as well, let's not duplicate it.
+				return;
+			}
+
 			var wheelEvent = $.Event( event );
 			wheelEvent.type = "wheel";
 			if ( delta ) {