UserListFragmentTest.kt

@RunWith(AndroidJUnit4::class)
class UserListFragmentTest {

    @Rule
    @JvmField
    var activityRule = ActivityTestRule(MainActivity::class.java, true, false)

    @Mock
    private lateinit var mockUserRepository: UserRepository

    private fun withRecyclerView(recyclerViewId: Int): RecyclerViewMatcher {
        return RecyclerViewMatcher(recyclerViewId)
    }

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

        val instrumentation = InstrumentationRegistry.getInstrumentation()
        val app = instrumentation.targetContext.applicationContext as CustomApplication

        val testComponent = DaggerTestApplicationComponent.builder()
                .testApplicationModule(TestApplicationModule(mockUserRepository))
                .build()
        app.component = testComponent
    }
    
    ...
}