title: Lumen - Generate fully-qualified url for an asset ex image - While running tests - phpunit tests/Controllers/FilesControllerTest.php
body: <p>I am very new to Lumen.</p>
  
  <p>I have path <code>public/profile/pic.png</code></p>
  
  <p>I want to generate url for this pic and save that url into databse.</p>
  
  <p>I tried function <code>url(public/profile/pic.png)</code>. Its creating as <code>http://public/profile/pic.png</code>. Not the correct url.</p>
  
  <p>I tried <code>asset(public/profile/pic.png)</code></p>
  
  <p>Error - <code>Call to undefined function asset</code>.
  I tried adding UrlGenerator class. But it says class not found.</p>
  
  <p>I am struck here. Please can anyone help me.</p>
  
  <p>EDIT:
  For me even url() is not working correctly. Its not creating correct url. <code>http://public/profile/pic.png</code>. Domain name is not getting added.
  And also - I tried adding UrlGenerator class. But it says class not found.</p>