title: How to mock an interface?
body: <p>Here is a question about Mockito. For the following code,</p>
  
  <pre><code>public class ABC implements someInterface() {
      public void test() {
          someFunction(new A(), this);
      }
  }
  </code></pre>
  
  <p><code>someFunction</code> accepts an instance of class A and a callback that implements <code>someInterface</code> as parameter. When using <code>powermock</code> to mock new instance creation, we can use</p>
  
  <pre><code>whenNew(A.class).withNoArguments().thenReturn(mMockClass);
  </code></pre>
  
  <p>then we can get the mock A class.</p>
  
  <p>The question is how do I mock the second parameter?</p>