title: PHPunit File Testing
body: <p>I'm relatively new to PHPUnit and TDD, and I was wondering how I might test the following code:</p>
  
  <pre><code>class File
  {
      /**
       * Write data to a given file
       * 
       * @param string $file
       * @param string $content
       * @return mixed
       */
      public function put($path, $content)
      {
          return file_put_contents($path, $content);
      }
  }
  </code></pre>
  
  <p>How can I test if the file was created WITHOUT actually creating the file (with PHPUnit obviously).</p>
  
  <p>Thanks.</p>