@Test
fun greeterSaysHello() {
    onView(withId(R.id.name_field)).perform(typeText("Steve"))
    onView(withId(R.id.greet_button)).perform(click())
    onView(withText("Hello Steve!")).check(matches(isDisplayed()))
}

The shape: onView(<matcher>).perform(<action>).check(<matches>).

The framework auto-waits via "synchronization conditions" per [espresso-doc][esp]:

"Each time a test invokes onView(), Espresso waits to perform the corresponding UI action or assertion until these synchronization conditions are met:

The message queue doesn't have any messages that Espresso needs to immediately process

There are no instances of AsyncTask currently executing a task

All developer-defined idling resources are idle"

This eliminates the need for Thread.sleep for stock Android async work.

When to use

An Android app needs UI tests in Google's first-party framework.
The team is not on cross-platform (Detox / Appium); pure Android stack.
A flake-prone Espresso suite needs the IdlingResource pattern to stabilize.

Step 1 - Add dependencies

// app/build.gradle
android {
    defaultConfig {
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }
}

dependencies {
    androidTestImplementation 'androidx.test.ext:junit:1.2.1'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.6.1'
    androidTestImplementation 'androidx.test.espresso:espresso-contrib:3.6.1'
    androidTestImplementation 'androidx.test.espresso:espresso-intents:3.6.1'
    androidTestImplementation 'androidx.test:rules:1.6.1'
}

Per [espresso-doc][esp], Espresso ships as multiple packages:

Package	Purpose
`espresso-core`	Core View matchers, actions, assertions.
`espresso-web`	WebView support.
`espresso-idling-resource`	Synchronization for background jobs.
`espresso-contrib`	DatePicker, RecyclerView, Drawer actions, accessibility checks.
`espresso-intents`	Intent validation + stubbing.
`espresso-remote`	Multi-process functionality.

Step 2 - Author tests

import androidx.test.espresso.Espresso.onView
import androidx.test.espresso.action.ViewActions.*
import androidx.test.espresso.assertion.ViewAssertions.*
import androidx.test.espresso.matcher.ViewMatchers.*
import androidx.test.ext.junit.rules.ActivityScenarioRule

@RunWith(AndroidJUnit4::class)
class CheckoutTest {
    @get:Rule
    val activityRule = ActivityScenarioRule(MainActivity::class.java)

    @Test
    fun applyPromoCode() {
        onView(withId(R.id.promo_field)).perform(typeText("WELCOME10"), closeSoftKeyboard())
        onView(withId(R.id.apply_button)).perform(click())
        onView(withId(R.id.subtotal)).check(matches(withText("$22.49")))
    }
}

Step 3 - IdlingResource for app-specific async

When the app uses something Espresso doesn't auto-track (e.g. custom thread pool, RxJava chains), wire an IdlingResource:

class NetworkIdlingResource : IdlingResource {
    @Volatile private var callback: IdlingResource.ResourceCallback? = null
    @Volatile private var pendingRequests = 0

    override fun getName() = "NetworkIdlingResource"
    override fun isIdleNow() = pendingRequests == 0
    override fun registerIdleTransitionCallback(cb: IdlingResource.ResourceCallback) {
        callback = cb
    }

    fun increment() = synchronized(this) { pendingRequests++ }
    fun decrement() = synchronized(this) {
        pendingRequests--
        if (pendingRequests == 0) callback?.onTransitionToIdle()
    }
}

// Wire from production code at network call sites:
networkIdlingResource.increment()
api.fetchOrders().enqueue { _, _ -> networkIdlingResource.decrement() }

// Register in test setup:
@Before fun setup() { IdlingRegistry.getInstance().register(networkIdlingResource) }
@After  fun teardown() { IdlingRegistry.getInstance().unregister(networkIdlingResource) }

Without IdlingResource, Espresso assumes idle when its built-in trackers report idle - async work the framework can't see triggers flake.

Step 4 - Common matchers and actions

// Matchers
withId(R.id.button)              // by ID
withText("Submit")                // by displayed text
withContentDescription("Login")   // by content description
hasSibling(withText("Email"))     // structural relationship
isDisplayed()                     // currently visible

// Actions
click(), longClick()
typeText("..."), clearText()
scrollTo(), swipeLeft(), swipeUp()
pressBack()

// Assertions
matches(withText("Hello"))
matches(isDisplayed())
matches(isEnabled())
doesNotExist()

Step 5 - RecyclerView interactions

// espresso-contrib provides RecyclerViewActions
onView(withId(R.id.cart_list))
    .perform(RecyclerViewActions.actionOnItemAtPosition<MyViewHolder>(0, click()))

onView(withId(R.id.cart_list))
    .perform(RecyclerViewActions.scrollTo<MyViewHolder>(hasDescendant(withText("BOOK-001"))))

Step 6 - Run

# Unit + UI tests on connected device / emulator
./gradlew connectedAndroidTest

# With test orchestrator (each test in fresh process - preferred for isolation):
android {
    defaultConfig {
        testInstrumentationRunnerArguments clearPackageData: 'true'
    }
    testOptions {
        execution 'ANDROIDX_TEST_ORCHESTRATOR'
    }
}

Step 7 - CI integration (Android emulator on GitHub Actions)

jobs:
  ui-tests:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v5
      - uses: reactivecircus/android-emulator-runner@v2
        with:
          api-level: 34
          script: ./gradlew connectedAndroidTest
      - uses: actions/upload-artifact@v4
        if: always()
        with:
          name: test-results
          path: app/build/outputs/androidTest-results

The test results land in JUnit XML at app/build/outputs/androidTest-results/.../TEST-*.xml - consumable by junit-xml-analysis (in the qa-test-reporting plugin).

Anti-patterns

Anti-pattern	Why it fails	Fix
`Thread.sleep` for async waits	Espresso has built-in sync; sleeps mask race conditions.	Use IdlingResource for unsupported async (Step 3).
`withText("Submit")` for buttons	Translation breaks the test.	`withId(R.id.submit_button)` or `withContentDescription`.
Missing `closeSoftKeyboard()` after typing	Keyboard obscures next view; `click()` misses.	Chain `closeSoftKeyboard()` after `typeText`.
Skipping `IdlingResource` for Retrofit / OkHttp	Network async invisible; flaky.	Wire IdlingResource (Step 3) OR use OkHttp's IdlingResource bridge.
One mega-test that asserts 10 things	One failure obscures others; debugging hard.	One assertion target per `@Test`.
Skipping test orchestrator	Tests share process; one test's state leaks.	Enable `ANDROIDX_TEST_ORCHESTRATOR` (Step 6).

Limitations

In-process only. Espresso runs in the app's process; no cross-app flows. Use UIAutomator for system-UI / multi-app interactions.
No iOS / web. Single-platform; for cross-platform see appium-testing.
Async opacity. Custom executors / coroutines need explicit IdlingResource integration.
Emulator slowness. Real devices ~2× faster than emulators for UI tests; consider device farms (Firebase Test Lab, AWS Device Farm) for matrix runs.

References

[esp][esp] - Espresso doc: small/predictable API, automatic synchronization (message queue / AsyncTask / IdlingResource), package list (-core, -web, -contrib, -idling-resource, -intents, -remote).
xcuitest-suite - iOS sibling.
appium-testing - cross-platform alternative.
junit-xml-analysis - downstream parser.

espresso-suite

espresso-suite

Overview