title: How to assertThat something is null with Hamcrest?
body: <p>How would I <code>assertThat</code> something is <code>null</code>?</p>
  
  <p>for example </p>
  
  <pre><code> assertThat(attr.getValue(), is(""));
  </code></pre>
  
  <p>But I get an error saying that I cannot have <code>null</code> in <code>is(null)</code>.</p>