Fixes #589: Add sample unit tests for a component

app/build.gradle

@@ -65,6 +65,16 @@ android {
     }
 }
 
+android.applicationVariants.all { variant ->
+    boolean hasTest = gradle.startParameter.taskNames.find {it.contains("test") || it.contains("Test")} != null
+    if (hasTest) {
+        apply plugin: 'kotlin-allopen'
+        allOpen {
+            annotation("org.mozilla.fenix.test.Mockable")
+        }
+    }
+}
+
 android.applicationVariants.all { variant ->
     def buildType = variant.buildType.name
 
@@ -152,10 +162,6 @@ dependencies {
     debugImplementation Deps.leakcanary
     releaseImplementation Deps.leakcanary_noop
 
-    testImplementation Deps.junit
-    androidTestImplementation Deps.tools_test_runner
-    androidTestImplementation Deps.tools_espresso_core
-
     armImplementation Deps.geckoview_nightly_arm
     x86Implementation Deps.geckoview_nightly_x86
     aarch64Implementation Deps.geckoview_nightly_aarch64
@@ -167,6 +173,17 @@ dependencies {
     implementation Deps.android_arch_navigation_ui
 
     implementation Deps.autodispose
+
+    androidTestImplementation Deps.tools_test_runner
+    androidTestImplementation Deps.tools_espresso_core
+
+    testImplementation Deps.junit_jupiter_api
+    testImplementation Deps.junit_jupiter_params
+    testImplementation Deps.junit_jupiter_engine
+
+    testImplementation Deps.mockito_core
+    androidTestImplementation Deps.mockito_android
+    testImplementation Deps.mockk
 }
 
 

app/src/main/java/org/mozilla/fenix/library/history/HistoryComponent.kt

@@ -4,6 +4,7 @@
 package org.mozilla.fenix.library.history
 
 import android.view.ViewGroup
+import org.mozilla.fenix.test.Mockable
 import org.mozilla.fenix.mvi.Action
 import org.mozilla.fenix.mvi.ActionBusFactory
 import org.mozilla.fenix.mvi.Change
@@ -25,6 +26,7 @@ data class HistoryItem(val id: Int, val url: String) {
     }
 }
 
+@Mockable
 class HistoryComponent(
     private val container: ViewGroup,
     bus: ActionBusFactory,

app/src/test/java/org/mozilla/fenix/ExampleUnitTest.kt

@@ -1,17 +0,0 @@
-package org.mozilla.fenix
-
-import org.junit.Test
-/* ktlint-disable no-wildcard-imports */
-import org.junit.Assert.*
-
-/**
- * Example local unit test, which will execute on the development machine (host).
- *
- * See [testing documentation](http://d.android.com/tools/testing).
- */
-class ExampleUnitTest {
-    @Test
-    fun addition_isCorrect() {
-        assertEquals(4, 2 + 2)
-    }
-}

app/src/test/java/org/mozilla/fenix/TestUtils.kt

@@ -0,0 +1,28 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+   License, v. 2.0. If a copy of the MPL was not distributed with this
+   file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.fenix
+
+import androidx.lifecycle.LifecycleOwner
+import io.mockk.Runs
+import io.mockk.every
+import io.mockk.just
+import io.mockk.mockk
+import io.reactivex.android.plugins.RxAndroidPlugins
+import io.reactivex.plugins.RxJavaPlugins
+import io.reactivex.schedulers.Schedulers
+import org.mozilla.fenix.mvi.ActionBusFactory
+
+object TestUtils {
+    fun setRxSchedulers() {
+        RxJavaPlugins.setIoSchedulerHandler { Schedulers.trampoline() }
+        RxAndroidPlugins.setInitMainThreadSchedulerHandler { Schedulers.trampoline() }
+    }
+
+    val owner = mockk<LifecycleOwner> {
+        every { lifecycle } returns mockk()
+        every { lifecycle.addObserver(any()) } just Runs
+    }
+    val bus: ActionBusFactory = ActionBusFactory.get(owner)
+}

app/src/test/java/org/mozilla/fenix/library/history/HistoryComponentTest.kt

@@ -0,0 +1,90 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+   License, v. 2.0. If a copy of the MPL was not distributed with this
+   file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.fenix.library.history
+
+import android.view.ViewGroup
+import io.mockk.MockKAnnotations
+import io.mockk.mockk
+import io.mockk.spyk
+import io.reactivex.Observer
+import io.reactivex.observers.TestObserver
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Test
+import org.mozilla.fenix.TestUtils.bus
+import org.mozilla.fenix.TestUtils.owner
+import org.mozilla.fenix.TestUtils.setRxSchedulers
+import org.mozilla.fenix.mvi.ActionBusFactory
+import org.mozilla.fenix.mvi.UIView
+import org.mozilla.fenix.mvi.getManagedEmitter
+
+class HistoryComponentTest {
+
+    private lateinit var historyComponent: TestHistoryComponent
+    private lateinit var historyObserver: TestObserver<HistoryState>
+    private lateinit var emitter: Observer<HistoryChange>
+
+    @BeforeEach
+    fun setup() {
+        MockKAnnotations.init(this)
+        setRxSchedulers()
+
+        historyComponent = spyk(
+            TestHistoryComponent(mockk(), bus),
+            recordPrivateCalls = true
+        )
+        historyObserver = historyComponent.internalRender(historyComponent.reducer).test()
+        emitter = owner.getManagedEmitter()
+    }
+
+    @Test
+    fun `add and remove one history item normally`() {
+        val historyItem = HistoryItem(123, "http://mozilla.org")
+
+        emitter.onNext(HistoryChange.Change(listOf(historyItem)))
+        emitter.onNext(HistoryChange.EnterEditMode(historyItem))
+        emitter.onNext(HistoryChange.RemoveItemForRemoval(historyItem))
+        emitter.onNext(HistoryChange.AddItemForRemoval(historyItem))
+        emitter.onNext(HistoryChange.ExitEditMode)
+
+        historyObserver.assertSubscribed().awaitCount(6).assertNoErrors()
+            .assertValues(
+                HistoryState(listOf(), HistoryState.Mode.Normal),
+                HistoryState(listOf(historyItem), HistoryState.Mode.Normal),
+                HistoryState(listOf(historyItem), HistoryState.Mode.Editing(listOf(historyItem))),
+                HistoryState(listOf(historyItem), HistoryState.Mode.Editing(listOf())),
+                HistoryState(listOf(historyItem), HistoryState.Mode.Editing(listOf(historyItem))),
+                HistoryState(listOf(historyItem), HistoryState.Mode.Normal)
+            )
+    }
+
+    @Test
+    fun `try making changes when not in edit mode`() {
+        val historyItems = listOf(
+            HistoryItem(1337, "http://reddit.com"),
+            HistoryItem(31337, "http://leethaxor.com")
+        )
+
+        emitter.onNext(HistoryChange.Change(historyItems))
+        emitter.onNext(HistoryChange.AddItemForRemoval(historyItems[0]))
+        emitter.onNext(HistoryChange.EnterEditMode(historyItems[0]))
+        emitter.onNext(HistoryChange.ExitEditMode)
+
+        historyObserver.assertSubscribed().awaitCount(4).assertNoErrors()
+            .assertValues(
+                HistoryState(listOf(), HistoryState.Mode.Normal),
+                HistoryState(historyItems, HistoryState.Mode.Normal),
+                HistoryState(historyItems, HistoryState.Mode.Editing(listOf(historyItems[0]))),
+                HistoryState(historyItems, HistoryState.Mode.Normal)
+            )
+    }
+
+    @Suppress("MemberVisibilityCanBePrivate")
+    class TestHistoryComponent(container: ViewGroup, bus: ActionBusFactory) :
+        HistoryComponent(container, bus) {
+
+        override val uiView: UIView<HistoryState, HistoryAction, HistoryChange>
+            get() = mockk(relaxed = true)
+    }
+}

architecture/src/main/java/org/mozilla/fenix/mvi/UIComponent.kt

@@ -17,19 +17,22 @@ abstract class UIComponent<S : ViewState, A : Action, C : Change>(
 
     abstract var initialState: S
     abstract val reducer: Reducer<S, C>
-    val uiView: UIView<S, A, C> by lazy { initView() }
+
+    open val uiView: UIView<S, A, C> by lazy { initView() }
 
     abstract fun initView(): UIView<S, A, C>
     open fun getContainerId() = uiView.containerId
-
     /**
      * Render the ViewState to the View through the Reducer
      */
     fun render(reducer: Reducer<S, C>): Disposable =
+            internalRender(reducer)
+            .subscribe(uiView.updateView())
+
+    fun internalRender(reducer: Reducer<S, C>): Observable<S> =
         changesObservable
             .scan(initialState, reducer)
             .distinctUntilChanged()
             .subscribeOn(Schedulers.io())
             .observeOn(AndroidSchedulers.mainThread())
-            .subscribe(uiView.updateView())
 }

architecture/src/main/java/org/mozilla/fenix/test/Mockable.kt

@@ -0,0 +1,7 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+   License, v. 2.0. If a copy of the MPL was not distributed with this
+   file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.fenix.test
+
+annotation class Mockable

build.gradle

@@ -9,6 +9,7 @@ buildscript {
         classpath Deps.tools_androidgradle
         classpath Deps.tools_kotlingradle
         classpath Deps.androidx_safeargs
+        classpath Deps.allopen
 
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files

buildSrc/src/main/java/Dependencies.kt

@@ -5,6 +5,7 @@
 private object Versions {
     const val kotlin = "1.3.11"
     const val android_gradle_plugin = "3.2.1"
+
     const val geckoNightly = "67.0.20190213102848"
     const val rxAndroid = "2.1.0"
     const val rxKotlin = "2.3.0"
@@ -23,13 +24,16 @@ private object Versions {
 
     const val mozilla_android_components = "0.43.0-SNAPSHOT"
 
-    const val junit = "4.12"
     const val test_tools = "1.0.2"
     const val espresso_core = "2.2.2"
 
     const val android_arch_navigation = "1.0.0-beta02"
 
     const val autodispose = "1.1.0"
+
+    const val junit_jupiter = "5.3.2"
+    const val mockito = "2.23.0"
+    const val mockk = "1.9.kotlin12"
 }
 
 @Suppress("unused")
@@ -38,6 +42,8 @@ object Deps {
     const val tools_kotlingradle = "org.jetbrains.kotlin:kotlin-gradle-plugin:${Versions.kotlin}"
     const val kotlin_stdlib = "org.jetbrains.kotlin:kotlin-stdlib-jdk7:${Versions.kotlin}"
 
+    const val allopen =  "org.jetbrains.kotlin:kotlin-allopen:${Versions.kotlin}"
+
     const val rxKotlin = "io.reactivex.rxjava2:rxkotlin:${Versions.rxKotlin}"
     const val rxAndroid = "io.reactivex.rxjava2:rxandroid:${Versions.rxAndroid}"
 
@@ -96,7 +102,6 @@ object Deps {
     const val leakcanary = "com.squareup.leakcanary:leakcanary-android:${Versions.leakcanary}"
     const val leakcanary_noop = "com.squareup.leakcanary:leakcanary-android-no-op:${Versions.leakcanary}"
 
-    const val junit = "junit:junit:${Versions.junit}"
     const val tools_test_runner = "com.android.support.test:runner:${Versions.test_tools}"
     const val tools_espresso_core = "com.android.support.test.espresso:espresso-core:${Versions.espresso_core}"
 
@@ -115,5 +120,13 @@ object Deps {
     const val autodispose_android = "com.uber.autodispose:autodispose-android:${Versions.autodispose}"
     const val autodispose_android_aac = "com.uber.autodispose:autodispose-android-archcomponents:${Versions.autodispose}"
     const val autodispose_android_aac_test = "com.uber.autodispose:autodispose-android-archcomponents-test:${Versions.autodispose}"
+
+    const val junit_jupiter_api = "org.junit.jupiter:junit-jupiter-api:${Versions.junit_jupiter}"
+    const val junit_jupiter_params = "org.junit.jupiter:junit-jupiter-params:${Versions.junit_jupiter}"
+    const val junit_jupiter_engine = "org.junit.jupiter:junit-jupiter-engine:${Versions.junit_jupiter}"
+
+    const val mockito_core = "org.mockito:mockito-core:${Versions.mockito}"
+    const val mockito_android = "org.mockito:mockito-android:${Versions.mockito}"
+    const val mockk = "io.mockk:mockk:${Versions.mockk}"
 }