title: Enabling HipHop syntax for PHP tests in TravisCI
body: <p>How can I enable HipHop syntax for PHP sources when running tests with TravisCI?</p>
  
  <p>I had the error below:</p>
  
  <pre><code>Fatal error: Syntax only allowed in Hack files (&lt;?hh) 
  or with -v Eval.EnableHipHopSyntax=true in 
  /home/travis/build/Corviz/framework/src/String/StringUtils.php 
  on line 20
  </code></pre>
  
  <p>The project itself is being developed to run primarily with php 7+, so the <code>&lt;?hh</code> is not an option. I could not find anything related until now.</p>
  
  <p>This is my configuration file: <a href="https://github.com/Corviz/framework/blob/master/.travis.yml" rel="nofollow">https://github.com/Corviz/framework/blob/master/.travis.yml</a></p>