title: Mock Node.js stream pipeline using Jest
body: <p>I have a method where I am using Node.js pipeline() that is having a last argument for a callback.</p>
  <pre><code>doSomething(readStream, destinationwritableStream): void {
     pipeline(readStream, destinationwritableStream, async () =&gt; {
        // some code here.
        // unable to cover this code using JEST
     })
  }
  </code></pre>
  <p>Any suggestions, how I can cover this async() callback or how to mock pipeline() method.</p>
  <p>Thanks in advance.</p>