testZindexBehavior() {
    // Don't use the default return values.
    fieldMock.$reset();
    fieldMock.getAppWindow().$anyTimes().$returns(window);
    fieldMock.getEditableDomHelper().$anyTimes().$returns(
        dom.getDomHelper(document));
    fieldMock.getBaseZindex().$returns(2);
    /** @suppress {visibility} suppression added to enable type checking */
    bubblePlugin.createBubbleContents = functions.UNDEFINED;
    fieldMock.$replay();

    bubblePlugin.createBubble(link);
    assertEquals(
        '2',
        '' + bubblePlugin.getSharedBubble_().bubbleContainer_.style.zIndex);

    fieldMock.$verify();
  }
@suppress {missingProperties,visibility} suppression added to enable type
     checking