Espresso Android UI Test Generator

Description

--- name: espresso-skill description: > 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", "Android UI test", or "instrumentation test". Triggers on: "Espresso", "onView", "ViewMatchers", "Android UI test", "instrumentation", "TestMu". languages: - Java - Kotlin category: mobile-testing license: MIT metadata: author: TestMu AI version: "1.0" --- # 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 ```kotlin @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) ```kotlin // 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) ```kotlin .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) ```kotlin .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) ```kotlin // 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 ```bash # 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 ```groovy 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 |

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