title: How to test file download in Behat
body: <p>There is this new Export functionality developed on this application and I'm trying to test it using Behat/Mink. 
  The issue here is when I click on the export link, the data on the page gets exported in to a CSV and gets saved under /Downloads but I don't see any response code or anything on the page.</p>
  
  <p>Is there a way I can export the CSV and navigate to the /Downloads folder to verify the file?</p>