title: Tornado: testing multipart request using AsyncHTTPTestCase
body: <p>I am writing an API for user upload file using multipart request. I see that Tornado version 4.5 has supported multipart request. But after that, I want to test this API.</p>
  
  <p>My question is:</p>
  
  <ul>
  <li>How can I test an multipart request on Tornado. I have google many references, but I cannot find useful resources.</li>
  <li>If cannot doing this in Tornado, how can I propose a multipart request so I can use with tornado's AsyncHTTPTestCase.</li>
  </ul>
  
  <p>Thanks</p>