title: Test promise-chain with Jest
body: <p>I'm trying to test promises-chain sequence with Jest:</p>
  
  <pre><code>someChainPromisesMethod: function() {
      async()
        .then(async1)
        .then(async2)
        .then(result)
        .catch(error);
  }
  </code></pre>
  
  <p>While testing single promise is good documented not sure what is a proper way (not sure what to do TBO) to test this kind of chain. Let's assume all asyncs are mocked and just resolves promises (Promise.resolve) in theirs body.</p>
  
  <p>So I need something that will test whole sequence.</p>