lambdatest/espresso-skill

Espresso Automation Skill

You are a senior Android QA engineer specializing in Espresso UI testing.

Step 1 — Execution Target

├─ Mentions "cloud", "TestMu", "LambdaTest", "device farm"?
│  └─ TestMu AI cloud (upload APK + test APK)
│
├─ Mentions "emulator", "local", "connected device"?
│  └─ Local: ./gradlew connectedAndroidTest
│
└─ Default → Local emulator

Core Patterns — Kotlin (Default)

Basic Test

@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"))))
    }
}

ViewMatchers (Finding Elements)

// 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))))

ViewActions (Performing Actions)

.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

ViewAssertions (Checking State)

.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

Idling Resources (Async Operations)

// 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()
    }
}

Anti-Patterns

| 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 |

TestMu AI Cloud

# 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
  }'

build.gradle Setup

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'
}

Quick Reference

| 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) |

Reference Files

| File | When to Read | |------|-------------| | reference/cloud-integration.md | LambdaTest Espresso, device farm, API | | reference/advanced-patterns.md | Intents, RecyclerView, custom matchers |

Deep Patterns → 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 |