I'm trying to write a simple UI test for my Android app:

@RunWith(AndroidJUnit4::class)
class SimpleTest {

    @get:Rule
    val activityRule = activityScenarioRule<MainActivity>()

    @Test
    fun justPass() {}
}

The problem is that this test hangs forever, and the app gets stuck at this screen:

It happens both on an emulator and on a real device. The complete title is androidx.test.core.app.InstrumentationActivityInvoker$EmptyActivity.

Strangely, the test completes if I press the square button and then select the same screen from the recent apps.

These are my test dependencies:

testImplementation 'junit:junit:4.13.1'
testImplementation "org.jetbrains.kotlinx:kotlinx-coroutines-test:$coroutines_version"
testImplementation 'android.arch.core:core-testing:2.1.0'
testImplementation "io.mockk:mockk:$mockk_version"
androidTestImplementation 'androidx.test:core-ktx:1.3.0'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'
androidTestImplementation 'androidx.test.ext:junit-ktx:1.1.2'
androidTestImplementation 'androidx.test:runner:1.3.0'
androidTestImplementation "io.mockk:mockk-android:$mockk_version"

If I add androidx.test:rules:1.3.0 and replace activityScenarioRule with ActivityTestRule, the test completes automatically as I expected. But ActivityTestRule has been deprecated, so I don't think that's a good option.

So what should I do to make this test pass without getting stuck?

Update

MainActivity is declared in the manifest with launch mode as single instance:

<activity android:name=".MainActivity"
    android:launchMode="singleInstance">
    ... 
</activity>

If I remove the launchMode attribute, the test no longer hangs. Still, it should be possible to test an activity that has that attribute, so I'm still looking for a solution.