Android Espresso Testing: Patterns That Actually Work in Production

Thread.sleep()

// Bad — arbitrary wait, brittle
onView(withId(R.id.save_button)).perform(click())
Thread.sleep(2000) // Hope 2s is enough
onView(withId(R.id.success_message)).check(matches(isDisplayed()))

// For coroutines, use a CoroutineIdlingResource or just structure tests to avoid this
// For simple cases, use ViewActions with explicit waits:
fun waitUntilVisible(viewId: Int, timeout: Long = 5000) {
    val endTime = System.currentTimeMillis() + timeout
    while (System.currentTimeMillis() < endTime) {
        try {
            onView(withId(viewId)).check(matches(isDisplayed()))
            return
        } catch (e: Exception) {
            Thread.sleep(50)
        }
    }
    throw AssertionError("View $viewId not visible within ${timeout}ms")
}

class LoginPage {
    fun enterEmail(email: String): LoginPage {
        onView(withId(R.id.email_input)).perform(
            clearText(), typeText(email), closeSoftKeyboard()
        )
        return this
    }
    
    fun enterPassword(password: String): LoginPage {
        onView(withId(R.id.password_input)).perform(
            clearText(), typeText(password), closeSoftKeyboard()
        )
        return this
    }
    
    fun submit(): HomePage {
        onView(withId(R.id.login_button)).perform(click())
        return HomePage()
    }
    
    fun verifyErrorMessage(message: String): LoginPage {
        onView(withId(R.id.error_text)).check(matches(withText(message)))
        return this
    }
}

// Test — clean, readable, resilient to selector changes
@Test
fun `invalid credentials show error message`() {
    LoginPage()
        .enterEmail("wrong@example.com")
        .enterPassword("wrongpassword")
        .submit()
        .verifyErrorMessage("Invalid credentials") // Wait — submit returns HomePage
        // Actually stay on LoginPage if login fails
}

LoginPage

RecyclerViewActions

// Click item at position
onView(withId(R.id.task_list))
    .perform(RecyclerViewActions.actionOnItemAtPosition<TaskViewHolder>(0, click()))

// Click item with specific text
onView(withId(R.id.task_list))
    .perform(RecyclerViewActions.actionOnItem<TaskViewHolder>(
        hasDescendant(withText("Buy groceries")),
        click()
    ))

// Scroll to item
onView(withId(R.id.task_list))
    .perform(RecyclerViewActions.scrollTo<TaskViewHolder>(
        hasDescendant(withText("Far down item"))
    ))

// Check item count
onView(withId(R.id.task_list))
    .check(matches(hasMinimumChildCount(3)))

// Match a view with specific background tint
fun hasBackgroundTint(@ColorInt color: Int): Matcher<View> {
    return object : BoundedMatcher<View, ImageView>(ImageView::class.java) {
        override fun describeTo(description: Description) {
            description.appendText("has background tint: $color")
        }
        
        override fun matchesSafely(view: ImageView): Boolean {
            val tint = view.backgroundTintList ?: return false
            return tint.defaultColor == color
        }
    }
}

// Usage
onView(withId(R.id.status_icon))
    .check(matches(hasBackgroundTint(Color.GREEN)))

@HiltAndroidTest
class LoginScreenTest {
    @get:Rule(order = 0)
    val hiltRule = HiltAndroidRule(this)
    
    @get:Rule(order = 1)
    val activityRule = ActivityScenarioRule(MainActivity::class.java)
    
    @Inject
    lateinit var authRepository: AuthRepository
    
    @Before
    fun setup() {
        hiltRule.inject()
        // Seed test data via injected fake repository
        (authRepository as FakeAuthRepository).addUser("test@example.com", "password123")
    }
    
    @Test
    fun `login with valid credentials navigates to home`() {
        onView(withId(R.id.email_input)).perform(typeText("test@example.com"), closeSoftKeyboard())
        onView(withId(R.id.password_input)).perform(typeText("password123"), closeSoftKeyboard())
        onView(withId(R.id.login_button)).perform(click())
        
        onView(withId(R.id.home_screen)).check(matches(isDisplayed()))
    }
}

// System dialogs (permissions)
device.findObject(UiSelector().text("Allow")).click()

// App dialogs (AlertDialog)
onView(withText("Delete")).inRoot(isDialog()).perform(click())

// Dismiss dialog
pressBack()

// Rule order is critical
@get:Rule(order = 0) // Hilt must initialize first
val hiltRule = HiltAndroidRule(this)

@get:Rule(order = 1) // Then the Activity starts (with Hilt injected)
val activityRule = ActivityScenarioRule(MainActivity::class.java)