title: How do I use Reactor's StepVerifier to verify a Mono is empty?
body: <p>I am using <code>StepVerifier</code> to test values:</p>
  
  <pre><code>@Test
  public void testStuff() {
      Thing thing = new Thing();
      Mono&lt;Thing&gt; result = Mono.just(thing);
      StepVerifier.create(result).consumeNextWith(r -&gt; {
          assertEquals(thing, r);
      }).verifyComplete();
  }
  </code></pre>
  
  <p>What I'd like to do now is test for the absence of an item in the Mono.  Like this:</p>
  
  <pre><code>@Test
  public void testNoStuff() {
      Mono&lt;Thing&gt; result = Mono.empty();
      StepVerifier.create(result)... // what goes here?
  }
  </code></pre>
  
  <p>I want to test that the Mono is in fact empty.  How do I do that?</p>