Hello, I'm trying to write an integration test for an Android application entirely written in Compose that has a single Activity and uses the Compose Navigation to change the screen content. I managed to properly interact and test the first screen that is shown by the navigation graph but, as soon as I navigate to a new destination, the test fails because it does not wait for the NavHost to load the new content. This is my current code for the test:

@RunWith(AndroidJUnit4::class)
class MainActivityTest {
    @get:Rule
    val composeTestRule = createAndroidComposeRule<MainActivity>()

    @Test
    fun appStartsWithoutCrashing() {
        composeTestRule.apply {
            // Check Switch
            onNodeWithTag(FirstScreen.CONSENT_SWITCH)
                .assertIsDisplayed()
                .assertIsOff()
                .performClick()
                .assertIsOn()

            // Click accept button
            onNodeWithTag(FirstScreen.ACCEPT_BUTTON)
                .assertIsDisplayed()
                .performClick()

            // Thread.sleep(500)

            // Check we are inside the second screen
            onNodeWithTag(SecondScreen.USERNAME_TEXT_FIELD)
                .assertIsDisplayed()
        }
    }
}

I'm sure that is a timing issue because if I add a

Thread.sleep(500)

before the

onNodeWithTag(SecondScreen.USERNAME_TEXT_FIELD).assertIsDisplayed()

, the test is successful. But I would like to avoid `Thread.sleep()`s in my code. Is there a better way to tell the

composeTestRule

to wait for the NavHost to load the new content before executing proceeding with the next assertion? PS I know that would be better to test the Composables in isolation, but I really need to simulate the user input on the App using Espresso and not only test the Composable behavior.

In a case like this,

ComposeTestRule.waitForIdle

might be your best bet to wait for everything to be idle before continuing. If you haven’t seen it already, https://developer.android.com/jetpack/compose/testing#sync goes through the different APIs and methods available for avoiding those pesky

Thread.sleep

s

Unfortunately I have already tried with

waitForIdle()

and it did not work

ComposeTestRule.waitUntil

would be your next best bet then

any suggestion for the condition of the

waitUntil

?

Nothing stopping you from checking for whether the node exists with that tag that you want to assert on later:

composeTestRule.waitUntil {
    composeTestRule
        .onAllNodesWithTag(SecondScreen.USERNAME_TEXT_FIELD)
        .fetchSemanticsNodes().size == 1
}

I’ll plug Jose’s recent article too which goes into more detail: https://medium.com/androiddevelopers/alternatives-to-idling-resources-in-compose-tests-8ae71f9fc473

Do you have a reference to your

NavController

in your test? Navigation only moves the current screen to

RESUMED

when the animation completes, which is exactly the kind of condition you'd want to use with

waitUntil

@Ian Lake I could expose the

NavController

but I suspect that there will still be some delay between the

NavController

changing the current route and the composables being actually available. But it's just a guess. @Alex Vanyo hey that actually worked! Thanks! I'm now checking Jose's medium post 🙂