Some similar notifications are not grouped together

@Test
    public void testCompositeNotifications() throws Exception
    {
        NotificationsUserProfilePage p;
        NotificationsTrayPage tray;
        // Now we enable "create", "update" and "comment" for user 2
        getUtil().login(SECOND_USER_NAME, SECOND_USER_PASSWORD);
        p = NotificationsUserProfilePage.gotoPage(SECOND_USER_NAME);
        p.setPageCreated(true);
        p.setPageUpdated(true);
        p.setPageCommented(true);

        // Create a page, edit it twice, and finally add a comment
        getUtil().login(FIRST_USER_NAME, FIRST_USER_PASSWORD);
        getUtil().createPage(getTestClassName(), "Linux", "Simple content", "Simple title");
        ViewPage page = getUtil().gotoPage(getTestClassName(), "Linux");
        page.edit();
        WikiEditPage edit = new WikiEditPage();
        edit.setContent("Linux is a part of GNU/Linux");
        edit.clickSaveAndContinue(true);
        edit.setContent("Linux is a part of GNU/Linux - it's the kernel");
        edit.clickSaveAndView(true);
        page = getUtil().gotoPage(getTestClassName(), "Linux");
        CommentsTab commentsTab = page.openCommentsDocExtraPane();
        commentsTab.postComment("Linux is a great OS", true);

        // Check that events have been grouped together (see: https://jira.xwiki.org/browse/XWIKI-14114)
        getUtil().login(SECOND_USER_NAME, SECOND_USER_PASSWORD);
        getUtil().gotoPage(getTestClassName(), "WebHome");
        tray = new NotificationsTrayPage();
        assertEquals(2, tray.getNotificationsCount());
        assertEquals("The document Simple title has been commented by user1.",
                tray.getNotificationContent(0));
        assertEquals("[create]", tray.getNotificationType(1));
        tray.clearAllNotifications();

    }