title: Error when trying to mock the NavController
body: <p>Trying to follow the example <a href="https://developer.android.com/guide/navigation/navigation-testing" rel="noreferrer">https://developer.android.com/guide/navigation/navigation-testing</a>, I have an expected error</p>
  
  <p><strong>org.mockito.exceptions.base.MockitoException:
  Mockito cannot mock this class: class androidx.navigation.NavController.</strong></p>
  
  <p>even after include all the dependencies as here: <a href="https://developer.android.com/training/testing/set-up-project" rel="noreferrer">https://developer.android.com/training/testing/set-up-project</a></p>
  
  <pre class="lang-java prettyprint-override"><code>@RunWith(AndroidJUnit4::class)
  class MyShopFragmentTest {
  
      @Test
      fun testMyShopScenario_F001() {
          // Create a mock NavController
          val mockNavController = mock(NavController::class.java)
  
          // Create a graphical FragmentScenario for the MyShopFragment
          val myShopFragmentScenario = launchFragmentInContainer&lt;MyShopFragment&gt;()
  
          // Set the NavController property on the fragment
          myShopFragmentScenario.onFragment { fragment -&gt;
              Navigation.setViewNavController(fragment.requireView(), mockNavController)
          }
  
          // Verify that performing a click prompts the correct Navigation action
          onView(ViewMatchers.withId(R.id.search)).perform(ViewActions.click())
          verify(mockNavController).navigate(R.id.searchFragment)
      }
  }
  </code></pre>
  
  <p>Any idea?</p>