add test for post-animation

Author: andrewseguin

src/lib/tooltip/tooltip.spec.ts

@@ -54,10 +54,16 @@ describe('MdTooltip', () => {
 
       // After the tooltip delay elapses, expect that the tooltip is not visible.
       tick(TOOLTIP_HIDE_DELAY);
+      fixture.detectChanges();
       expect(tooltipDirective._isTooltipVisible()).toBe(false);
+
+      // On animation complete, should expect that the tooltip has been detached.
+      fixture.whenStable().then(() => {
+        expect(tooltipDirective._tooltipInstance).toBeNull();
+      });
     }));
 
-    it('should not follow through with hide if show is called after', fakeAsync(() => {
+    it('should not follow through with hide if show is called after', fakeAsync(() => { 
       tooltipDirective.show();
       expect(tooltipDirective._isTooltipVisible()).toBe(true);
 

src/lib/tooltip/tooltip.ts

@@ -268,6 +268,7 @@ export class TooltipComponent {
   _afterVisibilityAnimation(e: AnimationTransitionEvent): void {
     if (e.toState === 'hidden' && !this.isVisible()) {
       this._onHide.next();
+
     }
   }