title: JUnit: should I do null-checks after assertNotNull
body: <p>Should I do null-checks after <code>assertNotNull</code> to avoid null-pointers in test code? E.g.</p>
  
  <pre><code>assertNotNull(foo);
  if (foo != null) {
      assertNotNull(foo.getBar());
  }
  </code></pre>
  
  <p>Or just</p>
  
  <pre><code>assertNotNull(foo);
  assertNotNull(foo.getBar());
  </code></pre>