title: Combine null safety and assertNotNull
body: <p>In test we usually have <code>assertNotNull</code>, but it does not perform smart cast from a nullable type to a non-nullable. I have to write something like this:</p>
  
  <pre><code>if (test == null) {
      Assert.fail("")
      return
  }
  </code></pre>
  
  <p>Is it a workaround to perform smart cast only with <code>assertNotNull</code> call? How do you deal with it?</p>