title: class must either be declared abstract or implement convertToLegacyCheckingEqualizer
body: <p>I wrote a simple Test case in IntelliJ 2017.1 Ultimate. And I see an absolutely bogus error message in IntelliJ</p>
  
  <pre><code>class must either be declared abstract or implement convertToLegacyCheckingEqualizer
  </code></pre>
  
  <p>My code compiles and runs absolutely fine but IntelliJ edition always shows this message for each and every test class.</p>
  
  <p>I googled and found totally unsatisfactory answers like</p>
  
  <pre><code>* I restarted my IDE to solve the problem
  * I deleted my idea project and recreated it to solve the problem
  * I cleared ivy cache to solve the problem.
  </code></pre>
  
  <p>This solutions are just wrong and don't really address the problem.</p>
  
  <p><a href="https://i.stack.imgur.com/AXSsF.png" rel="noreferrer"><img src="https://i.stack.imgur.com/AXSsF.png" alt="enter image description here"></a></p>