1. @Test
    2. public void start_http_server(TestContext context) {
    3.   Async async = context.async();
    5.   vertx.createHttpServer().requestHandler(req ->
    6.     req.response().putHeader("Content-Type", "text/plain").end("Ok"))
    8.     WebClient webClient = WebClient.create(vertx);
    10.       webClient.get(8080, "localhost", "/").send(ar -> {
    11.         if (ar.succeeded()) {
    12.           HttpResponse<Buffer> response = ar.result();
    13.           context.assertTrue(response.headers().contains("Content-Type"));
    14.           context.assertEquals("text/plain", response.getHeader("Content-Type"));
    15.           webClient.close();
    16.           async.complete();
    17.         } else {
    18.           async.resolve(Promise.failedPromise(ar.cause()));
    19.         }
    20.       });
    21.     }));