Ef fi cient Android UI Testing @alex_zhukovich https://alexzh.com/ 

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Multiple languages Light and Dark themes Accessibility options RTL and LTR support 

Let's Run The Tests 

ANDROID TESTS LOCAL INSTRUMENTATION 

ANDROID TESTS LOCAL INSTRUMENTATION UI* Non-UI 

ANDROID TESTS LOCAL INSTRUMENTATION UI* Non-UI UI Non-UI 

ANDROID TESTS LOCAL INSTRUMENTATION UI* Non-UI UI Non-UI SHARED CODE 

androidTest Requires device or emulator test Executes in local JVM 

androidTest test commonTest android { ... sourceSets { androidTest { java.srcDirs += "src/commonTest/java" } test { java.srcDirs += "src/commonTest/java" } } } 

User Interface tests Snapshot tests 

app.apk tests.apk BUILD APKs 

app.apk tests.apk >_ adb shell am instrument 

app.apk tests.apk >_ adb shell am instrument 

ACTIVITY VIEW / COMPOSABLE FRAGMENT 

launchActivity launchFragmentInContainer ComposeContentTestRule ActivityScenario.launch( MainActivity::class.java ) 

launchActivity launchFragmentInContainer ComposeContentTestRule val activityOptions = bundleOf( Pair("param-1", 1), Pair("param-2", 2), Pair("param-3", 3), ) val scenario = ActivityScenario.launch( MainActivity::class.java, activityOptions ) scenario.moveToState(Lifecycle.State.STARTED) ActivityScenario.launch( 

launchActivity launchFragmentInContainer ComposeContentTestRule val scenario = launchFragmentInContainer( fragmentArgs: Bundle? = null, @StyleRes themeResId: Int = 
 R.style.FragmentScenarioEmptyFragmentActivityTheme, initialState: Lifecycle.State = 
 Lifecycle.State.RESUMED, factory: FragmentFactory? = null ) scenario.moveToState(Lifecycle.State.STARTED) debugImplementation "androidx.fragment:fragment-testing:1.4.0-rc01" 

launchActivity launchFragmentInContainer ComposeContentTestRule Activity Fragment 

launchActivity launchFragmentInContainer ComposeContentTestRule androidx.fragment.app.testing.FragmentScenario$EmptyFragmentActivity Activity Fragment Compilation Added to AndroidManifest 

launchActivity launchFragmentInContainer ComposeContentTestRule @get:Rule val composeTestRule = createComposeRule() composeTestRule.apply { setContent { LoginScreen() } onNodeWithTag("email") .performTextInput("[email protected]") onNodeWithTag("password") .performTextInput("password") onNodeWithTag("login") .performClick() ... } debugImplementation "androidx.compose.ui:ui-test-manifest:1:0:5" 

launchActivity launchFragmentInContainer ComposeContentTestRule Component Activity @Composable 

launchActivity launchFragmentInContainer ComposeContentTestRule androidx.activity.ComponentActivity Component Activity @Composable Compilation Added to AndroidManifest 

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What Is a Good Test Case? 

Readable Stable Extendable Fast 

Readable Stable Extendable Fast 

onView(withId(R.id.emailEditText)) .perform(replaceText(email)) onView(withId(R.id.passwordEditText)) .perform(replaceText(password), closeSoftKeyboard()) onView(withId(R.id.loginButton)) .perform(click()) val progressBarIR = ViewVisibilityIdlingResource(...) IdlingRegistry.getInstance().register(progressBarIR) onView(withId(R.id.recyclerView)) .check(matches(withItemCount(13))) IdlingRegistry.getInstance().unregister(progressBarIR) onView(withId(R.id.navigation_profile)) .perform(click()) ... 

// Login screen onView(withId(R.id.emailEditText)) .perform(replaceText(email)) onView(withId(R.id.passwordEditText)) .perform(replaceText(password), closeSoftKeyboard()) onView(withId(R.id.loginButton)) .perform(click()) // Home screen val progressBarIR = ViewVisibilityIdlingResource(...) IdlingRegistry.getInstance().register(progressBarIR) onView(withId(R.id.recyclerView)) .check(matches(withItemCount(13))) IdlingRegistry.getInstance().unregister(progressBarIR) onView(withId(R.id.navigation_profile)) .perform(click()) ... 

onView(withId(R.id.email)) .perform(replaceText(EMAIL) onView(withId(R.id.password)) .perform(replaceText(PASSWORD) onView(withId(R.id.login)) .perform(click()) 

onView(withId(R.id.email)) login(EMAIL, PASSWORD) } 

onView(withId(R.id.email)) login(EMAIL, PASSWORD) } open class BaseTestRobot { fun enterText(viewId: Int, text: String) { onView(withId(viewId)) .perform(replaceText(text)) } fun clickOnView(viewId: Int) { onView(withId(viewId)) .perform(click()) } } 

onView(withId(R.id.email)) login(EMAIL, PASSWORD) } open class BaseTestRobot { fun login(email: String, password: String) { enterText(R.id.email, email) enterText(R.id.password, password) clickOnView(R.id.loginButton) } } 

onView(withId(R.id.email)) login(EMAIL, PASSWORD) } open class BaseTestRobot { LoginScreenRobot().apply { func() } 

BASIC OPERATIONS SCREEN ROBOTS TEST CASES @RunWith(AndroidJUnit4::class) class LoginActivityTest { @Test fun shouldBeDisplayedEmptyEmailErrorsWhenValueIsEmpty() { loginScreen { enterEmail(EMPTY_VALUE) emptyEmailErrorDisplayed() } } @Test fun shouldBeDisplayedEmailErrorsWhenValueIsNotEmail() { loginScreen { enterEmail(INCORRECT_EMAIL) incorrectEmailErrorDisplayed() } } @Test fun shouldBeDisplayedEmptyPasswordErrorsWhenValueIsEmpty() { loginScreen { enterPassword(EMPTY_VALUE) emptyPasswordErrorDisplayed() } } ... } class LoginScreenRobot : BaseTestRobot() { fun enterEmail(email: String) = enterText(R.id.email, email) fun enterPassword(email: String) = 
 enterText(R.id.password, password) ... } open class BaseTestRobot { fun enterText(viewId: Int, text: String) { onView(withId(viewId)) .perform(replaceText(text)) } fun clickOnView(viewId: Int) { onView(withId(viewId)) .perform(click()) } 
 ... } ESPRESSO 

BASIC OPERATIONS SCREEN ROBOTS TEST CASES @RunWith(AndroidJUnit4::class) class LoginActivityTest { @Test fun shouldBeDisplayedEmptyEmailErrorsWhenValueIsEmpty() { loginScreen { enterEmail(EMPTY_VALUE) emptyEmailErrorDisplayed() } } @Test fun shouldBeDisplayedEmailErrorsWhenValueIsNotEmail() { loginScreen { enterEmail(INCORRECT_EMAIL) incorrectEmailErrorDisplayed() } } @Test fun shouldBeDisplayedEmptyPasswordErrorsWhenValueIsEmpty() { loginScreen { enterPassword(EMPTY_VALUE) emptyPasswordErrorDisplayed() } } ... } class LoginScreenRobot : BaseTestRobot() { fun enterEmail(email: String) = enterText(R.id.email, email) fun enterPassword(email: String) = 
 enterText(R.id.password, password) ... } open class BaseTestRobot { fun enterText(viewId: Int, text: String) { val view = device.findObject(By.res(resId(viewId))) view.text = text } fun clickOnView(viewId: Int) { device.findObject(By.res(resIf(viewId))) 
 .click() } 
 ... } UI AUTOMATOR 

open class BaseTestRobot { @get:Rule val composeTestRule = createComposeRule() fun enterText(tag: String, text: String) { composeTestRule.onNodeWithTag(tag) .performTextInput(text) } fun clickOnView(tag: String) { composeTestRule.onNodeWithTag(tag) .performClick() } } @RunWith(AndroidJUnit4::class) class LoginActivityTest { @Test fun shouldBeDisplayedEmptyEmailErrorsWhenValueIsEmpty() { loginScreen { enterEmail(EMPTY_VALUE) emptyEmailErrorDisplayed() } } @Test fun shouldBeDisplayedEmailErrorsWhenValueIsNotEmail() { loginScreen { enterEmail(INCORRECT_EMAIL) incorrectEmailErrorDisplayed() } } @Test fun shouldBeDisplayedEmptyPasswordErrorsWhenValueIsEmpty() { loginScreen { enterPassword(EMPTY_VALUE) emptyPasswordErrorDisplayed() } } ... } BASIC OPERATIONS SCREEN ROBOTS TEST CASES COMPOSE UI TESTS class LoginScreenRobot : BaseTestRobot() { fun enterEmail(email: String) = enterText("email", email) fun enterPassword(email: String) = 
 enterText("password", password) ... } 

Challenges 
 In Mobile Testing 

Light and Dark themes 

YES NO RTL support 

Accessibility support Accessibility checks Hello … FONT SIZE Small, Default, Large, Largest DISPLAY SCALING Small, Default, Large, Largest 

Testing permissions 

Testing permissions UI interaction GrantPermissionRule ADB commands 

Testing permissions UI interaction GrantPermissionRule ADB commands Android Test Orchestrator 

Test Case Test Case Test Case Clean up data after test execution 

/data/data/PACKAGE/ databases fi les shared_prefs Clean up data after test execution 

databases fi les shared_prefs @get:Rul e val clearDatabaseRule = ClearDatabaseRule( ) @get:Rul e val clearFileRule = ClearFilesRule( ) @get:Rul e val clearPreferencesRule = ClearPreferencesRule( ) https://github.com/AdevintaSpain/Barista Clean up data after test execution 

Server Database Pre-populating the database 

Test Case Database DATA LAYER Query Dependencies UI interaction Pre-populating the database 

Real data vs Fake data Prod server Dev server Mock/Fake 

Real data vs Fake data Prod server Dev server DATA SYNCHRONIZATION We need to synchronize data between the production and dev servers. INTERACTION WITH THE SERVER We make requests to the production server. The connection can require certificates, VPN, etc. PRODUCTION BACK-END We always use the latest available production environment. 

Real data vs Fake data Mock/Fake DATA SYNCHRONIZATION We need to synchronize predefined responses with responses from the production server. NO INTERACTION WITH THE SERVER Responses from the production server can differ from the predefined data. We can use predefined fake responses instead of calling the production server. MAKE TESTS MORE STABLE 

End-To-End vs Functional tests 

INTERACTION WITH THE SERVER Interaction with the production server. ENTRY POINT Similar to the entry point of an app. END-TO-END TESTS 

FUNCTIONAL TESTS INTERACTION WITH THE SERVER Interaction with the non-production server. NAVIGATION Usually, navigation is not needed. ENTRY POINT We can start the test from a required Activity/Fragment. 

END-TO-END (E2E) TESTS FUNCTIONAL TESTS ENTRY POINT Similar to the entry point of an app. APP VERIFICATION Slow veri fi cation of the app. NAVIGATION Navigate to the required screen. SERVER INTERACTION Interaction with the production server. ENTRY POINT Start the required screen of the app. SERVER INTERACTION Usually interaction with non- production server. NAVIGATION Usually no navigation. UI VERIFICATION Fast veri fi cation of components or screens. 

END-TO-END TESTS FUNCTIONAL TESTS 

Flaky Tests 

External dependencies Framework Test case execution Device and emulator 

External dependencies - Network connection (VPN) - Network speed - Back-end 

Framework - Framework issues - Toast, Snackbar, etc - Custom Views 

Device and emulator - Performance - Noti fi cations - Device memory 

Test case execution - Simulate User actions - Incorrect state before/after a test case - Toast, Snackbar, etc 

- Network connection (VPN) - Network speed - Back-end - Framework issues - Toast, Snackbar, etc - Custom Views - Simulate User actions - Incorrect state before/after a test case - Toast, Snackbar, etc - Performance - Noti fi cations - Device memory External dependencies Framework Test case execution Device and emulator 

Best Practices 

PAY ATTENTION TO NAMING 

NO "SLEEP" IN TESTS 

ALL TEST CASES SHOULD BE INDEPENDENT 

USE MULTIPLE SMALL TESTS INSTEAD OF ONE BIG TEST 

DO NOT SPEND TIME NAVIGATING TO THE REQUIRED SCREEN 

FOLLOW THE 
 "NO FLAKY TESTS" POLICY 

DO NOT RELY ONLY ON 
 UI TEST AUTOMATION 

LEARN YOUR TOOLS 

@alex_zhukovich https://alexzh.com/ THANK YOU FOR LISTENING!