testContextMenuKeyboard() {
    popup.attach(anchor, null, null, true);
    popup.hide();
    assertFalse(popup.isVisible());
    events.fireKeySequence(anchor, KeyCodes.SPACE);
    assertFalse(popup.isVisible());
    events.fireKeySequence(anchor, KeyCodes.ENTER);
    assertFalse(popup.isVisible());
  }
Tests that a context menu isn't shown if the SPACE or ENTER keys are
     pressed.