MockWebServer is getting error HTTP FAILED: java.net.ConnectException: Failed to connect to localhost/127.0.0.1:8080

I'm working on Android instrumentation tests with MockWebServer of Square. Here are the codes that I'm trying to run. However, I'm getting error from Okhttp client, when I ran the test. I've added network configurations

HTTP FAILED: java.net.ConnectException: Failed to connect to localhost/127.0.0.1:8080

@UninstallModules(
  UrlModule::class
)
@HiltAndroidTest
@RunWith(AndroidJUnit4::class)
class MainActivityTest {

@get:Rule
val hiltRule = HiltAndroidRule(this)

private val mockWebServer = MockWebServer()

@Inject
lateinit var okHttp: OkHttpClient

private lateinit var okHttp3IdlingResource: OkHttp3IdlingResource

@Before
fun setup() {
    hiltRule.inject()
    okHttp3IdlingResource = OkHttp3IdlingResource.create("okhttp", okHttp)
    IdlingRegistry.getInstance().register(okHttp3IdlingResource)
    IdlingRegistry.getInstance().register(TestIdlingResource.countingIdlingResource)
    mockWebServer.dispatcher = MockServerDispatcher().RequestDispatcher()
    mockWebServer.start()
}


@Test
fun screenIsReady() {
    val scenario = launchActivity<MainActivity>()
    onView(withId(R.id.recyclerViewMovies)).check { view, noViewFoundException ->
        if (noViewFoundException != null) {
            throw noViewFoundException
        }
        val recyclerView = view as RecyclerView
        assertEquals(20, recyclerView.adapter?.itemCount)
    }
    scenario.close()
}

@Module
@InstallIn(SingletonComponent::class)
class FakeBaseUrlModule {

    @Provides
    @Singleton
    fun provideUrl(): String = "http://localhost:8080/"
}

@After
fun teardown() {
   mockWebServer.shutdown()
   IdlingRegistry.getInstance().unregister(okHttp3IdlingResource)
   IdlingRegistry.getInstance().unregister(TestIdlingResource.countingIdlingResource)
}

I'm waiting your comments. Thank you.

I noticed my mistake. The solution is pretty easy. I should have started the server with port number like mockWebServer.start(8080).

Regards