michael@0: var tab;
michael@0: 
michael@0: function test() {
michael@0:   waitForExplicitFinish();
michael@0: 
michael@0:   tab = gBrowser.addTab();
michael@0:   isnot(tab.getAttribute("fadein"), "true", "newly opened tab is yet to fade in");
michael@0: 
michael@0:   // Try to remove the tab right before the opening animation's first frame
michael@0:   window.mozRequestAnimationFrame(checkAnimationState);
michael@0: }
michael@0: 
michael@0: function checkAnimationState() {
michael@0:   is(tab.getAttribute("fadein"), "true", "tab opening animation initiated");
michael@0: 
michael@0:   info(window.getComputedStyle(tab).maxWidth);
michael@0:   gBrowser.removeTab(tab, { animate: true });
michael@0:   if (!tab.parentNode) {
michael@0:     ok(true, "tab removed synchronously since the opening animation hasn't moved yet");
michael@0:     finish();
michael@0:     return;
michael@0:   }
michael@0: 
michael@0:   info("tab didn't close immediately, so the tab opening animation must have started moving");
michael@0:   info("waiting for the tab to close asynchronously");
michael@0:   tab.addEventListener("transitionend", function (event) {
michael@0:     if (event.propertyName == "max-width") {
michael@0:       tab.removeEventListener("transitionend", arguments.callee, false);
michael@0:       executeSoon(function () {
michael@0:         ok(!tab.parentNode, "tab removed asynchronously");
michael@0:         finish();
michael@0:       });
michael@0:     }
michael@0:   }, false);
michael@0: }