### Question:
AuthWindow extends Window implements Button.ClickListener { @Override public void attach() { super.attach(); int posX = (int)(getApplication().getMainWindow().getWidth() - this.getWidth())/2; int posY = (int)(getApplication().getMainWindow().getHeight() - this.getHeight())/2; setPositionX(posX); setPositionY(posY); if (showOptions) hostField.focus(); else usernameField.focus(); } AuthWindow(String host, int port); @Override void attach(); @Override void buttonClick(ClickEvent event);  }### Answer:
@Test public void testAttach(){ assertTrue(app.getMainWindow().getChildWindows().contains(normalWindow)); app.getMainWindow().removeWindow(normalWindow); assertFalse(app.getMainWindow().getChildWindows().contains(normalWindow)); }