> Generates Espresso UI tests for Android apps in Kotlin or Java. Espresso runs inside the app process for fast, reliable UI testing. Supports local and TestMu AI cloud real devices. Use when user mentions "Espresso", "onView", "ViewMatchers", "onView", "ViewMatchers", "Android UI test", "instrumentation", "TestMu".
npx skills add https://github.com/LambdaTest/agent-skills --skill espresso-skill
You are a senior Android QA engineer specializing in Espresso UI testing.
├─ Mentions "cloud", "TestMu", "LambdaTest", "device farm"?
│ └─ TestMu AI cloud (upload APK + test APK)
│
├─ Mentions "emulator", "local", "connected device"?
│ └─ Local: ./gradlew connectedAndroidTest
│
└─ Default → Local emulator
@RunWith(AndroidJUnit4::class)
class LoginTest {
@get:Rule
val activityRule = ActivityScenarioRule(LoginActivity::class.java)
@Test
fun loginWithValidCredentials() {
// Type email
onView(withId(R.id.emailInput))
.perform(typeText("[email protected]"), closeSoftKeyboard())
// Type password
onView(withId(R.id.passwordInput))
.perform(typeText("password123"), closeSoftKeyboard())
// Click login button
onView(withId(R.id.loginButton))
.perform(click())
// Verify dashboard is displayed
onView(withId(R.id.dashboardTitle))
.check(matches(isDisplayed()))
.check(matches(withText("Welcome")))
}
@Test
fun loginWithInvalidCredentials_showsError() {
onView(withId(R.id.emailInput))
.perform(typeText("[email protected]"), closeSoftKeyboard())
onView(withId(R.id.passwordInput))
.perform(typeText("wrong"), closeSoftKeyboard())
onView(withId(R.id.loginButton))
.perform(click())
onView(withId(R.id.errorText))
.check(matches(isDisplayed()))
.check(matches(withText(containsString("Invalid"))))
}
}
// By ID (best)
onView(withId(R.id.loginButton))
// By text
onView(withText("Login"))
// By content description (accessibility)
onView(withContentDescription("Submit form"))
// By hint text
onView(withHint("Enter your email"))
// Combined matchers
onView(allOf(withId(R.id.button), withText("Submit"), isDisplayed()))
// In RecyclerView
onView(withId(R.id.recyclerView))
.perform(RecyclerViewActions.actionOnItemAtPosition<ViewHolder>(0, click()))
// By parent
onView(allOf(withText("Delete"), isDescendantOfA(withId(R.id.toolbar))))
.perform(click()) // Tap
.perform(longClick()) // Long press
.perform(typeText("hello")) // Type text
.perform(replaceText("new text")) // Replace text
.perform(clearText()) // Clear field
.perform(closeSoftKeyboard()) // Dismiss keyboard
.perform(scrollTo()) // Scroll to element
.perform(swipeUp()) // Swipe gesture
.perform(swipeDown())
.perform(swipeLeft())
.perform(swipeRight())
.perform(pressBack()) // Back button
.check(matches(isDisplayed())) // Visible
.check(matches(not(isDisplayed()))) // Not visible
.check(matches(withText("Expected"))) // Text matches
.check(matches(isEnabled())) // Enabled
.check(matches(isChecked())) // Checkbox checked
.check(matches(hasErrorText("Required"))) // Error text
.check(doesNotExist()) // Not in hierarchy
// Register before test
@Before
fun setUp() {
IdlingRegistry.getInstance().register(myIdlingResource)
}
// Unregister after test
@After
fun tearDown() {
IdlingRegistry.getInstance().unregister(myIdlingResource)
}
// Custom IdlingResource for network calls
class NetworkIdlingResource : IdlingResource {
private var callback: IdlingResource.ResourceCallback? = null
private var isIdle = true
override fun getName() = "NetworkIdlingResource"
override fun isIdleNow() = isIdle
override fun registerIdleTransitionCallback(callback: ResourceCallback) {
this.callback = callback
}
fun setIdle(idle: Boolean) {
isIdle = idle
if (idle) callback?.onTransitionToIdle()
}
}
| Bad | Good | Why |
|-----|------|-----|
| Thread.sleep() | IdlingResources | Espresso auto-syncs UI thread |
| XPath-like traversal | withId(R.id.x) | Direct ID is fastest |
| Testing across activities | Test single screen, mock data | Isolation |
| No closeSoftKeyboard() | Always close after typeText() | Keyboard blocks elements |
# 1. Build APK and test APK
./gradlew assembleDebug assembleDebugAndroidTest
# 2. Upload both to LambdaTest
curl -u "$LT_USERNAME:$LT_ACCESS_KEY" \
-X POST "https://manual-api.lambdatest.com/app/upload/realDevice" \
-F "appFile=@app/build/outputs/apk/debug/app-debug.apk" \
-F "type=android"
curl -u "$LT_USERNAME:$LT_ACCESS_KEY" \
-X POST "https://manual-api.lambdatest.com/app/upload/realDevice" \
-F "appFile=@app/build/outputs/apk/androidTest/debug/app-debug-androidTest.apk" \
-F "type=android"
# 3. Execute on real devices via API
curl -u "$LT_USERNAME:$LT_ACCESS_KEY" \
-X POST "https://mobile-api.lambdatest.com/framework/v1/espresso/build" \
-H "Content-Type: application/json" \
-d '{
"app": "lt://APP123",
"testSuite": "lt://TEST456",
"device": ["Pixel 8-14", "Galaxy S24-14"],
"build": "Espresso Cloud Build",
"video": true, "deviceLog": true
}'
android {
defaultConfig {
testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
}
}
dependencies {
androidTestImplementation 'androidx.test.espresso:espresso-core:3.5.1'
androidTestImplementation 'androidx.test.espresso:espresso-contrib:3.5.1'
androidTestImplementation 'androidx.test.espresso:espresso-intents:3.5.1'
androidTestImplementation 'androidx.test:runner:1.5.2'
androidTestImplementation 'androidx.test:rules:1.5.0'
androidTestImplementation 'androidx.test.ext:junit:1.1.5'
}
| Task | Command/Code |
|------|-------------|
| Run all tests | ./gradlew connectedAndroidTest |
| Run specific class | ./gradlew connectedAndroidTest -Pandroid.testInstrumentationRunnerArguments.class=com.example.LoginTest |
| Run on specific device | ./gradlew connectedAndroidTest -PtestDevice=emulator-5554 |
| Intent verification | Intents.init() → intended(hasComponent(...)) → Intents.release() |
| RecyclerView scroll | RecyclerViewActions.scrollToPosition<>(10) |
| Screenshot | Screenshot.capture(activityRule.activity) |
| File | When to Read |
|------|-------------|
| reference/cloud-integration.md | LambdaTest Espresso, device farm, API |
| reference/advanced-patterns.md | Intents, RecyclerView, custom matchers |
reference/playbook.md| § | Section | Lines |
|---|---------|-------|
| 1 | Project Setup | Gradle deps, Orchestrator |
| 2 | Test Structure & Lifecycle | Rules, permissions, annotations |
| 3 | Custom Matchers & ViewActions | RecyclerView, wait, scroll |
| 4 | RecyclerView Testing | Scroll, click child, swipe, assert |
| 5 | Idling Resources | Counting, OkHttp, custom |
| 6 | Intent Testing | Share, stub, camera |
| 7 | MockWebServer for API Tests | Enqueue, error handling |
| 8 | CI/CD Integration | GitHub Actions, emulator runner |
| 9 | Debugging Quick-Reference | 10 common problems |
| 10 | Best Practices Checklist | 13 items |
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Take lambdatest/espresso-skill from the repository into ~/.claude/skills for personal
use, or into .claude/skills inside a project.
The agent identifies a skill by the name field in its header. Two skills with the
same name cannot sit side by side — one of them will be ignored.