title: Difference between `willReturn()` and `will($this->returnValue())` in PHPUnit?
body: <p>In PHPUnit, is there <em>any</em> difference between</p>
  
  <p><code>$mockFoo-&gt;method('methodName')-&gt;will($this-&gt;returnValue($mockBar));</code></p>
  
  <p>and</p>
  
  <p><code>$mockFoo-&gt;method('methodName')-&gt;willReturn($mockBar);</code></p>