@Override
  public void shutdown() throws Exception {
    doAction(Executable::shutdown);
  }
@Test
  public void shouldStopAll() throws Exception {
    // When:
    multiExecutable.shutdown();

    // Then:
    final InOrder inOrder = Mockito.inOrder(executable1, executable2);
    inOrder.verify(executable1).shutdown();
    inOrder.verify(executable2).shutdown();
    inOrder.verifyNoMoreInteractions();
  }