Example UI test implementation

project/app-common/build.gradle

@@ -1,6 +1,8 @@
 plugins {
     alias(libs.plugins.android.library)
     alias(libs.plugins.kotlin.android)
+    alias(libs.plugins.kotlin.kapt)
+    alias(libs.plugins.hilt)
 }
 
 android {
@@ -29,7 +31,21 @@ android {
     }
 }
 
+hilt {
+    // This flag reduces incremental compilation times by reducing how often an incremental change causes a rebuild of the Dagger components.
+    // See https://dagger.dev/hilt/gradle-setup.html#aggregating-task
+    enableAggregatingTask = true
+}
+
+kapt {
+    // If Hilt is used in a Kotlin project, then Kapt should be configured to keep the correct error types.
+    // See https://dagger.dev/hilt/gradle-setup.html#using-hilt-with-kotlin
+    correctErrorTypes = true
+}
+
 dependencies {
+    libsHelper.addDependencyInjectionDependencies(it)
+
     implementation libs.kotlin
     coreLibraryDesugaring libs.jdk.desugar
 

project/app-common/src/main/java/mobi/lab/sample/app/common/di/IdlerModule.kt

@@ -0,0 +1,18 @@
+package mobi.lab.sample.app.common.di
+
+import dagger.Module
+import dagger.Provides
+import dagger.hilt.InstallIn
+import dagger.hilt.components.SingletonComponent
+import mobi.lab.sample.app.common.test.Idler
+import mobi.lab.sample.app.common.test.NoOpIdler
+import javax.inject.Singleton
+
+@Module
+@InstallIn(SingletonComponent::class)
+object IdlerModule {
+
+    @Provides
+    @Singleton
+    internal fun provideIdler(): Idler = NoOpIdler()
+}

project/app-common/src/main/java/mobi/lab/sample/app/common/test/Idler.kt

@@ -0,0 +1,46 @@
+package mobi.lab.sample.app.common.test
+
+interface Idler {
+    /**
+     * Create a new [IdlerToken]. This does not mark the token as busy
+     *
+     * @return new [IdlerToken]
+     */
+    fun token(): IdlerToken
+
+    /**
+     * Create a new [IdlerToken] and mark it as busy.
+     *
+     * @return new [IdlerToken]
+     */
+    fun busy(): IdlerToken
+
+    /**
+     * Create a new [IdlerToken] from the given key and mark it as busy.
+     *
+     * @param key Any object to use as a value for the token.
+     * @return new [IdlerToken] using the key
+     */
+    fun busy(key: Any): IdlerToken
+
+    /**
+     * Mark the [IdlerToken] as busy.
+     *
+     * @param token [IdlerToken]
+     */
+    fun busy(token: IdlerToken)
+
+    /**
+     * Mark work identified by key as done.
+     *
+     * @param key Any object that identifies the work
+     */
+    fun done(key: Any)
+
+    /**
+     * Mark work identified by token as done.
+     *
+     * @param token [IdlerToken]
+     */
+    fun done(token: IdlerToken)
+}

project/app-common/src/main/java/mobi/lab/sample/app/common/test/IdlerToken.kt

@@ -0,0 +1,3 @@
+package mobi.lab.sample.app.common.test
+
+data class IdlerToken(val key: Any)

project/app-common/src/main/java/mobi/lab/sample/app/common/test/NoOpIdler.kt

@@ -0,0 +1,28 @@
+package mobi.lab.sample.app.common.test
+
+class NoOpIdler : Idler {
+
+    override fun token(): IdlerToken {
+        return IdlerToken(Any())
+    }
+
+    override fun busy(): IdlerToken {
+        return IdlerToken(Any())
+    }
+
+    override fun busy(key: Any): IdlerToken {
+        return IdlerToken(key)
+    }
+
+    override fun busy(token: IdlerToken) {
+        // Do nothing
+    }
+
+    override fun done(key: Any) {
+        // Do nothing
+    }
+
+    override fun done(token: IdlerToken) {
+        // Do nothing
+    }
+}

project/app/build.gradle

@@ -53,6 +53,7 @@ android {
         targetSdkVersion(libs.versions.android.sdk.target.get())
         minSdkVersion(libs.versions.android.sdk.min.get())
         applicationId = "mobi.lab.sample"
+        testInstrumentationRunner = "mobi.lab.sample.util.CustomTestRunner"
 
         versionCode = project.ext.versionCode
         versionName = project.ext.versionName
@@ -158,6 +159,7 @@ tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).configureEach {
 dependencies {
     libsHelper.addDependencyInjectionDependencies(it)
     libsHelper.addUnitTestDependencies(it)
+    libsHelper.addInstrumentationTestDependencies(it)
 
     implementation libs.kotlin
     implementation libs.androidx.legacy

project/app/src/androidTest/java/mobi/lab/sample/TestApp.kt

@@ -0,0 +1,7 @@
+package mobi.lab.sample
+
+import dagger.hilt.android.testing.CustomTestApplication
+
+// Hilt will generate an application class that extends TestAppBase
+@CustomTestApplication(TestAppBase::class)
+interface TestApp

project/app/src/androidTest/java/mobi/lab/sample/TestAppBase.kt

@@ -0,0 +1,16 @@
+package mobi.lab.sample
+
+import android.app.Application
+import androidx.test.espresso.IdlingRegistry
+import mobi.lab.sample.util.RealIdler
+import timber.log.Timber
+
+open class TestAppBase : Application() {
+
+    override fun onCreate() {
+        super.onCreate()
+        // Any other relevant setup we need to make
+        Timber.plant(Timber.DebugTree())
+        IdlingRegistry.getInstance().register(RealIdler.idlingResource)
+    }
+}

project/app/src/androidTest/java/mobi/lab/sample/demo/login/LoginActivityTest.kt

@@ -0,0 +1,124 @@
+package mobi.lab.sample.demo.login
+
+import androidx.test.espresso.Espresso
+import androidx.test.espresso.Espresso.onView
+import androidx.test.espresso.action.ViewActions.click
+import androidx.test.espresso.action.ViewActions.typeText
+import androidx.test.espresso.assertion.ViewAssertions.matches
+import androidx.test.espresso.intent.Intents
+import androidx.test.espresso.intent.matcher.IntentMatchers
+import androidx.test.espresso.matcher.RootMatchers.isDialog
+import androidx.test.espresso.matcher.ViewMatchers.isDisplayed
+import androidx.test.espresso.matcher.ViewMatchers.withId
+import androidx.test.espresso.matcher.ViewMatchers.withText
+import androidx.test.ext.junit.rules.activityScenarioRule
+import dagger.hilt.android.testing.HiltAndroidRule
+import dagger.hilt.android.testing.HiltAndroidTest
+import mobi.lab.sample.R
+import mobi.lab.sample.common.rx.SchedulerProvider
+import mobi.lab.sample.demo.main.MainActivity
+import mobi.lab.sample.util.hasNoTextInputLayoutError
+import mobi.lab.sample.util.hasTextInputLayoutError
+import org.junit.After
+import org.junit.Before
+import org.junit.Rule
+import org.junit.Test
+import javax.inject.Inject
+
+@HiltAndroidTest
+class LoginActivityTest {
+
+    @get:Rule
+    var hiltRule = HiltAndroidRule(this)
+
+    /**
+     * Use [androidx.test.ext.junit.rules.ActivityScenarioRule] to create and launch the activity under test before each test,
+     * and close it after each test. This is a replacement for
+     * [androidx.test.rule.ActivityTestRule].
+     */
+    @get:Rule
+    val activityScenarioRule = activityScenarioRule<LoginActivity>()
+
+    @Inject
+    lateinit var schedulers: SchedulerProvider
+
+    private lateinit var activity: LoginActivity
+
+    @Before
+    fun setup() {
+        hiltRule.inject()
+        Intents.init()
+        activityScenarioRule.scenario.onActivity {
+            activity = it
+        }
+    }
+
+    @After
+    fun tearDown() {
+        Intents.release()
+    }
+
+    @Test
+    fun show_input_error_when_fields_are_empty_rxidler() {
+        onView(withId(R.id.button_login)).perform(click())
+
+        onView(withId(R.id.input_layout_email)).check(matches(hasTextInputLayoutError(TEXT_ID_REQUIRED)))
+        onView(withId(R.id.input_layout_password)).check(matches(hasTextInputLayoutError(TEXT_ID_REQUIRED)))
+
+        Intents.assertNoUnverifiedIntents()
+    }
+
+    @Test
+    fun show_input_error_when_only_username_is_filled_rxidler() {
+        onView(withId(R.id.edit_text_email)).perform(typeText("asd"))
+        onView(withId(R.id.button_login)).perform(click())
+
+        onView(withId(R.id.input_layout_email)).check(matches(hasNoTextInputLayoutError()))
+        onView(withId(R.id.input_layout_password)).check(matches(hasTextInputLayoutError(TEXT_ID_REQUIRED)))
+
+        Intents.assertNoUnverifiedIntents()
+    }
+
+    @Test
+    fun show_input_error_when_only_password_is_filled_rxidler() {
+        onView(withId(R.id.edit_text_password)).perform(typeText("asd"))
+        onView(withId(R.id.button_login)).perform(click())
+
+        onView(withId(R.id.input_layout_email)).check(matches(hasTextInputLayoutError(TEXT_ID_REQUIRED)))
+        onView(withId(R.id.input_layout_password)).check(matches(hasNoTextInputLayoutError()))
+
+        Intents.assertNoUnverifiedIntents()
+    }
+
+    @Test
+    fun login_success_when_fields_are_filled_rxidler() {
+        onView(withId(R.id.edit_text_email)).perform(typeText("asd"))
+        onView(withId(R.id.edit_text_password)).perform(typeText("asd"))
+        onView(withId(R.id.button_login)).perform(click())
+
+        Intents.intended(IntentMatchers.hasComponent(MainActivity::class.java.name))
+    }
+
+    @Test
+    fun show_error_dialog_when_login_fails_rxidler() {
+        // "test" is a keyword to trigger an error response. See LoginUseCase implementation
+        onView(withId(R.id.edit_text_email)).perform(typeText("test"))
+        onView(withId(R.id.edit_text_password)).perform(typeText("asd"))
+        onView(withId(R.id.button_login)).perform(click())
+
+        // Validate the dialog and close it
+        onView(withText(R.string.error_generic))
+            .inRoot(isDialog())
+            .check(matches(isDisplayed()))
+        Espresso.pressBack()
+
+        onView(withId(R.id.input_layout_email)).check(matches(hasNoTextInputLayoutError()))
+        onView(withId(R.id.input_layout_password)).check(matches(hasNoTextInputLayoutError()))
+
+        Intents.assertNoUnverifiedIntents()
+    }
+
+    companion object {
+        private val TEXT_ID_REQUIRED = R.string.demo_text_required
+    }
+}

project/app/src/androidTest/java/mobi/lab/sample/di/SchedulerModuleTest.kt

@@ -0,0 +1,38 @@
+package mobi.lab.sample.di
+
+import dagger.hilt.android.testing.HiltAndroidRule
+import dagger.hilt.android.testing.HiltAndroidTest
+import io.reactivex.rxjava3.android.schedulers.AndroidSchedulers
+import io.reactivex.rxjava3.schedulers.Schedulers
+import mobi.lab.sample.common.rx.SchedulerProvider
+import org.junit.Before
+import org.junit.Rule
+import org.junit.Test
+import javax.inject.Inject
+import kotlin.test.assertSame
+
+/**
+ * A sample test showing how to inject dependencies via Dagger.
+ * Verifies that our TestAppComponent gets its schedulers from TestSchedulerModule
+ */
+@HiltAndroidTest
+class SchedulerModuleTest {
+
+    @get:Rule
+    var hiltRule = HiltAndroidRule(this)
+
+    @Inject
+    lateinit var schedulers: SchedulerProvider
+
+    @Before
+    fun setup() {
+        hiltRule.inject()
+    }
+
+    @Test
+    fun verify_test_schedulers() {
+        assertSame(schedulers.main, AndroidSchedulers.mainThread())
+        assertSame(schedulers.io, Schedulers.io())
+        assertSame(schedulers.computation, Schedulers.computation())
+    }
+}

project/app/src/androidTest/java/mobi/lab/sample/di/TestIdlerModule.kt

@@ -0,0 +1,24 @@
+package mobi.lab.sample.di
+
+import dagger.Module
+import dagger.Provides
+import dagger.hilt.components.SingletonComponent
+import dagger.hilt.testing.TestInstallIn
+import mobi.lab.sample.app.common.di.IdlerModule
+import mobi.lab.sample.app.common.test.Idler
+import mobi.lab.sample.util.RealIdler
+import javax.inject.Singleton
+
+@Module
+@TestInstallIn(
+    components = [SingletonComponent::class],
+    replaces = [IdlerModule::class]
+)
+object TestIdlerModule {
+
+    @Singleton
+    @Provides
+    fun provideIdler(): Idler {
+        return RealIdler
+    }
+}

project/app/src/androidTest/java/mobi/lab/sample/di/TestSchedulerModule.kt

@@ -0,0 +1,24 @@
+package mobi.lab.sample.di
+
+import dagger.Module
+import dagger.Provides
+import dagger.hilt.components.SingletonComponent
+import dagger.hilt.testing.TestInstallIn
+import mobi.lab.sample.app.common.test.Idler
+import mobi.lab.sample.common.rx.SchedulerProvider
+import mobi.lab.sample.util.TestSchedulerProvider
+import javax.inject.Singleton
+
+@Module
+@TestInstallIn(
+    components = [SingletonComponent::class],
+    replaces = [SchedulerModule::class]
+)
+object TestSchedulerModule {
+
+    @Singleton
+    @Provides
+    fun provideSchedulerProvider(idler: Idler): SchedulerProvider {
+        return TestSchedulerProvider(idler)
+    }
+}