testDispose() {
    control.render(sandbox);
    /** @suppress {visibility} suppression added to enable type checking */
    const handler = control.getHandler();
    /** @suppress {visibility} suppression added to enable type checking */
    const keyHandler = control.getKeyHandler();
    control.dispose();
    assertFalse(
        'Control must no longer be in the document', control.isInDocument());
    assertTrue('Control must have been disposed of', control.isDisposed());
    assertUndefined('Renderer must have been deleted', control.getRenderer());
    assertNull('Content must be nulled out', control.getContent());
    assertTrue(
        'Event handler must have been disposed of', handler.isDisposed());
    assertUndefined(
        'Event handler must have been deleted',
        control.googUiComponentHandler_);
    assertTrue(
        'Key handler must have been disposed of', keyHandler.isDisposed());
    assertUndefined('Key handler must have been deleted', control.keyHandler_);
    assertNull(
        'Extra class names must have been nulled out',
        control.getExtraClassNames());
  }
Tests {@link Control#dispose}.
@suppress {visibility} suppression added to
     enable type checking