title: check that method returns instance of corresponding class
body: <p>I have a simple method that creates new object (in reality it creates rather complex object)</p>
  
  <pre><code>class MyClass {
      public MyObject create() { return new MyObject(); }
  }
  </code></pre>
  
  <p>I want to test that upon <code>create</code> call it returns isntance of <code>MyObject</code>.
  How to do that using <code>mockito</code>?</p>
  
  <pre><code>public MyClassTest {
      @Mock
      private MyClass myClassMock;
  
      @Test
      public void testCreate() {
          ???
      }
  </code></pre>