HelpIcon extends Composite { public void setHelpTitle(final String title) { popover.setTitle(title); popover.reconfigure(); } HelpIcon();   HelpIcon(Icon icon,
             SimplePanel panel,
             Popover popover); void setHelpTitle(final String title); void setHelpContent(final String content);  }
@Test public void setHelpTitle() { helpIcon.setHelpTitle("testTitle"); verify(popover).setTitle("testTitle"); }