How to test SavedStateHandle in Type Safety Navigation Compose?

Question

I'm working on an Android project that uses Type Safety Compose Navigation (androidx.navigation:navigation-compose:2.8.0-beta05). I’m trying to create a test to verify a value passed through SavedStateHandle.

See my code:

// Screen.kt

@Serializable
sealed class Screen {
    @Serializable
    data class Details(
        val movieId: Int,
    ) : Screen()
}

// DetailsViewModel.kt

import androidx.navigation.toRoute
import com.paulohc.movlist.navigation.Screen

class DetailsViewModel @Inject constructor(
    savedStateHandle: SavedStateHandle,
) : ViewModel() {
    val movieId: Int = savedStateHandle.toRoute<Screen.Details>().movieId
}

I tried the following test:

// DetailsViewModelTest.kt

class DetailsViewModelTest {
    private lateinit var detailsViewModel: DetailsViewModel

    @BeforeEach
    fun setup() {
        val savedState = SavedStateHandle(mapOf("movieId" to 10))
        detailsViewModel = DetailsViewModel(savedState)
    }

    @Test
    fun getState() {
        assertThat(detailsViewModel.movieId).isEqualTo(10)
    }
}

But I am encountering the following error:

Method putInt in android.os.BaseBundle not mocked. See https://developer.android.com/r/studio-ui/build/not-mocked for details.
java.lang.RuntimeException: Method putInt in android.os.BaseBundle not mocked. See https://developer.android.com/r/studio-ui/build/not-mocked for details.

How can I rewrite this test to pass correctly? Can I mock the ´savedStateHandle´ with mockk?

Are you trying to test this with a JUnit test? Anything that references Android classes like Bundle (like these APIs do) needs to be an instrumented test or use Robolectric. — ianhanniballake
– ianhanniballake, Commented Aug 13, 2024 at 6:40
Yeah! I am trying test this with JUnit test. I noticed that savedStateHandle.toRoute() has an Android dependency on android.os.Bundle, as you can see in the following links: issuetracker.google.com/issues/349807172?pli=1 and issuetracker.google.com/issues/340966212?hl=it — Paulo Henrique
– Paulo Henrique, Commented Aug 13, 2024 at 18:07

Hugo Landim · Accepted Answer · 2024-12-11 09:27:41Z

5

Try using this Test rule bellow:

class SavedStateHandleRule(
    private val route: Any,
) : TestWatcher() {
    val savedStateHandleMock: SavedStateHandle = mockk()
    override fun starting(description: Description?) {
        mockkStatic("androidx.navigation.SavedStateHandleKt")
        every { savedStateHandleMock.internalToRoute<Any>(any(), any()) } returns route
        super.starting(description)
    }

    override fun finished(description: Description?) {
        unmockkStatic("androidx.navigation.SavedStateHandleKt")
        super.finished(description)
    }
}

The on the Test class:

@get:Rule
val savedStateHandleRule = SavedStateHandleRule(Screen.Details(movieId=123)

private val viewModel: DetailsViewModel get() = DetailsViewModel(savedStateHandleRule.savedStateHandleMock)

answered Dec 11, 2024 at 9:27

Hugo Landim

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1 Comment

Hugo Landim Jun 13 at 14:16

Update: The workaround does not work with 2.9.0 anymore, since internalToRoute cannot be resolved.

Sahar Vanunu · Accepted Answer · 2024-11-24 08:54:28Z

4

I found workaround solution :

Using mockk

mockkStatic("androidx.navigation.SavedStateHandleKt")
every { saveStateHandle.toRoute<Page.Login>() } returns Page.Login(fromLogout = false)

also created an extension for it :

inline fun <reified T : Any> SavedStateHandle.mockkToRoute(page: T) {
    mockkStatic("androidx.navigation.SavedStateHandleKt")
    every { toRoute<T>() } returns page
}

Usage :

saveStateHandle.mockkToRoute(Page.Login(fromLogout = false))

The issue it using android dependencies android.os.Bundle so for not using robotelectric, i used it :)

answered Nov 24, 2024 at 8:54

Sahar Vanunu

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