Testing Navigation component: "does not have a NavController"

I'm implementing Espresso tests. I'm using a Fragment with a NavGraph scoped ViewModel. The problem is when I try to test the Fragment I got an IllegalStateException because the Fragment does not have a NavController set. How can I fix this problem?

class MyFragment : Fragment(), Injectable {

    private val viewModel by navGraphViewModels<MyViewModel>(R.id.scoped_graph){
        viewModelFactory
   }

    @Inject
    lateinit var viewModelFactory: ViewModelProvider.Factory
    //Other stuff
}

Test class:

class FragmentTest {

    class TestMyFragment: MyFragment(){
        val navMock = mock<NavController>()

        override fun getNavController(): NavController {
            return navMock
        }
    }

    @Mock
    private lateinit var viewModel: MyViewModel
    private lateinit var scenario: FragmentScenario<TestMyFragment>

    @Before
    fun prepareTest(){
        MockitoAnnotations.initMocks(this)

    scenario = launchFragmentInContainer<TestMyFragment>(themeResId = R.style.Theme_AppCompat){
        TestMyFragment().apply {
            viewModelFactory = ViewModelUtil.createFor(viewModel)
        }
    }

    // My test
}

Exception I got:

java.lang.IllegalStateException: View android.widget.ScrollView does not have a NavController setjava.lang.IllegalStateException

from Testing Navigation component: "does not have a NavController"