title: Vertx unit test never finishes
body: <p>I have a vertx unit test with vertx version 3.3.2 and JUnit version 4.12.
  The following unit test never finishes:</p>
  
  <pre><code>@RunWith(VertxUnitRunner.class)
  public class SomeVerticleTest {
  
      private Vertx vertx;
  
      @Before
      public void before(TestContext context) {
          vertx = Vertx.vertx();
          vertx.deployVerticle(SomeVerticle.class.getName(), r -&gt; context.asyncAssertSuccess()); // problem is in this line, see answer for solution!
      }
  
      @Test
      public void doStuff(TestContext context) {
          String encodedMessage = Json.encode("myMessage");
          Async async = context.async();
          vertx.eventBus().send("someVerticle", encodedMessage, asyncResult -&gt; {
              // some context.asserts on the message reply
              async.complete(); // this line is executed, I can see it in the debugger
          });
      }
  }
  </code></pre>
  
  <p>The test itself runs fine, the message is sent, correctly processed by the handler in <code>SomeVerticle</code> and the reply is created and sent correctly.</p>
  
  <p>But: Although the method <code>doStuff</code> is executed and its success is published to the <code>Async</code> object, the test just runs forever, it never ends. This can be verified by adding an after-test method, annotated with <code>@After</code> which is never executed.</p>
  
  <p>I have tried to find the error for two hours now, but I simply don't know what exactly the problem might be, so I would be happy about any assistance.</p>
  
  <p><strong>[update]</strong>
  After two minutes, the test fails with a timeout.</p>
  
  <p><strong>[update 2]</strong>
  I found the problem and put it into a separate answer.</p>