Increase code coverage (pt5).

formula-android-tests/build.gradle.kts

@@ -1,5 +1,5 @@
 plugins {
-    id("com.android.application")
+    id("com.android.library")
     id("kotlin-android")
     id("kotlin-parcelize")
 }
@@ -10,19 +10,6 @@ apply {
 
 android {
     namespace = "com.instacart.formula"
-    defaultConfig {
-        applicationId = "com.instacart.formula"
-        versionCode = 1
-        versionName = "1.0"
-        testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
-    }
-
-    buildTypes {
-        release {
-            isMinifyEnabled = false
-            proguardFiles(getDefaultProguardFile("proguard-android-optimize.txt"), "proguard-rules.pro")
-        }
-    }
 
     testOptions {
         unitTests {
@@ -47,4 +34,5 @@ dependencies {
     testImplementation(libs.junit)
     testImplementation(libs.robolectric)
     testImplementation(libs.truth)
+    testImplementation(project(":test-utils:android"))
 }

formula-android-tests/src/main/AndroidManifest.xml

@@ -34,19 +34,5 @@
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
-
-        <activity android:name="com.instacart.formula.NonBoundActivityTest$TestActivity">
-            <intent-filter>
-                <action android:name="android.intent.action.MAIN" />
-                <category android:name="android.intent.category.LAUNCHER" />
-            </intent-filter>
-        </activity>
-
-        <activity android:name="com.instacart.formula.NonBoundFragmentActivityTest$TestActivity">
-            <intent-filter>
-                <action android:name="android.intent.action.MAIN" />
-                <category android:name="android.intent.category.LAUNCHER" />
-            </intent-filter>
-        </activity>
     </application>
 </manifest>

formula-android-tests/src/test/java/com/instacart/formula/NonBoundActivityTest.kt

@@ -1,10 +1,10 @@
 package com.instacart.formula
 
 import android.app.Activity
-import androidx.fragment.app.FragmentActivity
 import androidx.test.core.app.ActivityScenario
 import androidx.test.ext.junit.rules.ActivityScenarioRule
 import androidx.test.ext.junit.runners.AndroidJUnit4
+import com.instacart.testutils.android.TestActivity
 import org.junit.Before
 import org.junit.Rule
 import org.junit.Test
@@ -16,7 +16,6 @@ import org.junit.runner.RunWith
  */
 @RunWith(AndroidJUnit4::class)
 class NonBoundActivityTest {
-    class TestActivity : Activity()
 
     private val formulaRule = TestFormulaRule(
         initFormula = { app ->

formula-android-tests/src/test/java/com/instacart/formula/NonBoundFragmentActivityTest.kt

@@ -1,33 +1,31 @@
 package com.instacart.formula
 
-import androidx.fragment.app.FragmentActivity
 import androidx.test.core.app.ActivityScenario
 import androidx.test.ext.junit.rules.ActivityScenarioRule
 import androidx.test.ext.junit.runners.AndroidJUnit4
+import com.instacart.testutils.android.TestFragmentActivity
 import org.junit.Before
 import org.junit.Rule
 import org.junit.Test
 import org.junit.rules.RuleChain
 import org.junit.runner.RunWith
 
 /**
- * Tests that formula-android module handles non-bound activities gracefully.
+ * Tests that formula-android module handles non-bound fragment activities gracefully.
  */
 @RunWith(AndroidJUnit4::class)
 class NonBoundFragmentActivityTest {
-    class TestActivity : FragmentActivity()
-
     private val formulaRule = TestFormulaRule(
         initFormula = { app ->
             FormulaAndroid.init(app) {}
         }
     )
 
-    private val activityRule = ActivityScenarioRule(TestActivity::class.java)
+    private val activityRule = ActivityScenarioRule(TestFragmentActivity::class.java)
 
     @get:Rule
     val rule = RuleChain.outerRule(formulaRule).around(activityRule)
-    lateinit var scenario: ActivityScenario<TestActivity>
+    lateinit var scenario: ActivityScenario<TestFragmentActivity>
 
     @Before
     fun setup() {

formula-android/build.gradle.kts

@@ -16,6 +16,7 @@ android {
 
     testOptions {
         unitTests.isReturnDefaultValues = true
+        unitTests.isIncludeAndroidResources = true
     }
 
     publishing {
@@ -40,5 +41,6 @@ dependencies {
     testImplementation(libs.mockito.kotlin)
     testImplementation(libs.robolectric)
     testImplementation(libs.truth)
+    testImplementation(project(":test-utils:android"))
 }
 

formula-android/src/main/java/com/instacart/formula/android/internal/ActivityStoreContextImpl.kt

@@ -59,7 +59,7 @@ internal class ActivityStoreContextImpl<Activity : FragmentActivity> : ActivityS
         select: Activity.() -> Observable<Event>
     ): Observable<Event> {
         // TODO: should probably use startedActivity
-        return activityAttachEvents()
+        return attachEventRelay
             .switchMap {
                 val activity = activity
                 if (activity == null) {
@@ -105,8 +105,8 @@ internal class ActivityStoreContextImpl<Activity : FragmentActivity> : ActivityS
     fun detachActivity(activity: Activity) {
         if (this.activity == activity) {
             this.activity = null
+            attachEventRelay.accept(false)
         }
-        attachEventRelay.accept(false)
     }
 
     fun updateFragmentLifecycleState(id: FragmentId, newState: Lifecycle.State) {
@@ -121,8 +121,6 @@ internal class ActivityStoreContextImpl<Activity : FragmentActivity> : ActivityS
         fragmentStateUpdated.accept(contract.tag)
     }
 
-    private fun activityAttachEvents(): Observable<Boolean> = attachEventRelay
-
     private fun fragmentLifecycleState(tag: String): Observable<Lifecycle.State> {
         return fragmentStateUpdated
             .filter { it == tag }

formula-android/src/test/java/com/instacart/formula/android/internal/ActivityStoreContextTest.kt

@@ -0,0 +1,92 @@
+package com.instacart.formula.android.internal
+
+import android.os.Looper
+import androidx.fragment.app.FragmentActivity
+import androidx.test.core.app.ActivityScenario
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import com.google.common.truth.Truth.assertThat
+import com.instacart.testutils.android.TestFragmentActivity
+import com.instacart.testutils.android.activity
+import com.instacart.testutils.android.executeOnBackgroundThread
+import com.instacart.testutils.android.throwOnTimeout
+import org.junit.Test
+import org.junit.runner.RunWith
+import java.util.concurrent.CountDownLatch
+
+@RunWith(AndroidJUnit4::class)
+class ActivityStoreContextTest {
+
+    @Test fun `started activity returns null until onActivityStarted is called`() {
+        val scenario = ActivityScenario.launch(TestFragmentActivity::class.java)
+        val storeContext = ActivityStoreContextImpl<TestFragmentActivity>()
+
+        // Initially null
+        assertThat(storeContext.startedActivity()).isNull()
+
+        // After attach
+        storeContext.attachActivity(scenario.activity())
+        assertThat(storeContext.startedActivity()).isNull()
+
+        // After on started
+        storeContext.onActivityStarted(scenario.activity())
+        assertThat(storeContext.startedActivity()).isEqualTo(scenario.activity())
+    }
+
+    @Test fun `detaches only if the activity matches`() {
+        val scenario = ActivityScenario.launch(TestFragmentActivity::class.java)
+        val storeContext = ActivityStoreContextImpl<TestFragmentActivity>()
+
+        val oldActivity = scenario.activity()
+        val newActivity = scenario.recreate().activity()
+
+        storeContext.attachActivity(newActivity)
+        storeContext.onActivityStarted(newActivity)
+        storeContext.detachActivity(oldActivity)
+
+        assertThat(storeContext.startedActivity()).isEqualTo(newActivity)
+    }
+
+    @Test fun `send posts events on the main thread`() {
+        val scenario = ActivityScenario.launch(TestFragmentActivity::class.java)
+        val storeContext = ActivityStoreContextImpl<TestFragmentActivity>()
+        storeContext.attachActivity(scenario.activity())
+        storeContext.onActivityStarted(scenario.activity())
+
+        val effectThread = mutableListOf<Looper?>()
+        storeContext.send { effectThread.add(Looper.myLooper()) }
+        storeContext.sendOnBackgroundThread { effectThread.add(Looper.myLooper()) }
+
+        assertThat(effectThread).containsExactly(
+            Looper.getMainLooper(), Looper.getMainLooper()
+        )
+    }
+
+    @Test
+    fun `send drops the action if there is no started activity`() {
+        val storeContext = ActivityStoreContextImpl<TestFragmentActivity>()
+
+        val effectThread = mutableListOf<Looper?>()
+        storeContext.send { effectThread.add(Looper.myLooper()) }
+
+        val result = runCatching {
+            storeContext.sendOnBackgroundThread { effectThread.add(Looper.myLooper()) }
+        }
+        assertThat(effectThread).isEmpty()
+        assertThat(result.exceptionOrNull()).hasMessageThat().contains(
+            "timeout"
+        )
+    }
+
+    private fun <ActivityType : FragmentActivity> ActivityStoreContextImpl<ActivityType>.sendOnBackgroundThread(
+        action: ActivityType.() -> Unit
+    ) {
+        val sendLatch = CountDownLatch(1)
+        executeOnBackgroundThread {
+            send {
+                action()
+                sendLatch.countDown()
+            }
+        }
+        sendLatch.throwOnTimeout()
+    }
+}

settings.gradle.kts

@@ -17,3 +17,6 @@ include(
     ":samples:stopwatch-compose",
     ":samples:todoapp"
 )
+include(
+    ":test-utils:android"
+)

test-utils/android/.gitignore

@@ -0,0 +1 @@
+/build

test-utils/android/build.gradle.kts

@@ -0,0 +1,20 @@
+plugins {
+    id("com.android.library")
+    id("kotlin-android")
+    id("kotlin-parcelize")
+}
+
+android {
+    namespace = "com.instacart.testutils.android"
+}
+
+dependencies {
+    implementation(project(":formula-rxjava3"))
+    implementation(project(":formula-android"))
+
+    implementation(libs.kotlin)
+    implementation(libs.androidx.appcompat)
+    implementation(libs.androidx.test.core.ktx)
+    implementation(libs.lifecycle.extensions)
+    implementation(libs.robolectric)
+}

test-utils/android/src/main/AndroidManifest.xml

@@ -0,0 +1,14 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <application>
+        <activity
+            android:name="com.instacart.testutils.android.TestFragmentActivity"
+            android:launchMode="standard"
+            android:exported="false" />
+
+        <activity
+            android:name="com.instacart.testutils.android.TestActivity"
+            android:launchMode="standard"
+            android:exported="false" />
+    </application>
+</manifest>

test-utils/android/src/main/java/com/instacart/testutils/android/TestActivity.kt

@@ -0,0 +1,5 @@
+package com.instacart.testutils.android
+
+import android.app.Activity
+
+class TestActivity : Activity()

test-utils/android/src/main/java/com/instacart/testutils/android/TestExtensions.kt

@@ -0,0 +1,37 @@
+package com.instacart.testutils.android
+
+import android.app.Activity
+import android.os.Looper
+import androidx.test.core.app.ActivityScenario
+import org.robolectric.Shadows
+import java.util.concurrent.CountDownLatch
+import java.util.concurrent.Executors
+import java.util.concurrent.TimeUnit
+
+fun <A: Activity> ActivityScenario<A>.activity(): A {
+    return get { this }
+}
+
+fun <A: Activity, T> ActivityScenario<A>.get(select: A.() -> T): T {
+    val list: MutableList<T> = mutableListOf()
+    onActivity {
+        list.add(it.select())
+    }
+    return list.first()
+}
+
+fun CountDownLatch.throwOnTimeout() {
+    if (!await(100, TimeUnit.MILLISECONDS)) {
+        throw IllegalStateException("timeout")
+    }
+}
+
+fun executeOnBackgroundThread(action: () -> Unit) {
+    val initLatch = CountDownLatch(1)
+    Executors.newSingleThreadExecutor().execute {
+        action()
+        initLatch.countDown()
+    }
+    initLatch.throwOnTimeout()
+    Shadows.shadowOf(Looper.getMainLooper()).idle()
+}

test-utils/android/src/main/java/com/instacart/testutils/android/TestFragmentActivity.kt

@@ -0,0 +1,5 @@
+package com.instacart.testutils.android
+
+import androidx.fragment.app.FragmentActivity
+
+class TestFragmentActivity : FragmentActivity()