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Espresso Skill

> 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".

6k tokens
context cost
the whole folder, loaded on every use
4
files
instructions only
0
copies elsewhere
how many repositories repackaged it
343
stars on the repo
on the repository, not the skill itself

Install

one command, takes just this skill from the repository
npx skills add https://github.com/LambdaTest/agent-skills --skill espresso-skill

The instruction itself

14 sections, as written by the author

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 |

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How to use it

Copy the folder

Take lambdatest/espresso-skill from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

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