### Question:
TCPFrontend { public void stop () { for (NetServer server : servers) { server.close(); } } TCPFrontend(Vertx vertx, IGameServer gameServer); void start(); void stop();  }### Answer:
@Test public void testStartAndStop () throws InterruptedException { Vertx vertx = Vertx.vertx(); IGameServer gameServer = Mockito.mock(IGameServer.class); TCPFrontend server = new TCPFrontend(vertx, gameServer); Thread.sleep(1000); server.stop(); vertx.close(); }