app/build.gradle.kts

@@ -147,6 +147,12 @@ android {
     }
 
     testOptions {
+        // Robolectric-backed Compose UI unit tests (issue #373) need the merged Android resources
+        // (drawables, strings, the compiled resource table) on the JVM unit-test classpath so
+        // `stringResource(...)` and Material3 theming resolve without an emulator. Off by default in
+        // AGP; JVM tests that don't touch resources are unaffected.
+        unitTests.isIncludeAndroidResources = true
+
         // Gradle Managed Devices define the per-API E2E matrix as config-as-code: one virtual
         // device per supported Android version (a rolling ~7-year window, API 29 → latest stable).
         // Run the whole matrix with `./gradlew e2eGroupDebugAndroidTest`, or one level with e.g.
@@ -251,7 +257,14 @@ val jacocoGeneratedExcludes = listOf(
 // audit): unlike `jacocoGeneratedExcludes` above, none of this is generated code — it is hand-written
 // but structurally unreachable from a JVM unit test, so counting it against the metric just measures
 // how much Compose/framework glue exists rather than how well the logic is tested. Four buckets:
-//  1. Compose screen/component render code — only exercisable via a Compose UI test or an emulator.
+//  1. Compose screen/component render code. Historically only exercisable via an emulator, so it was
+//     excluded here. Issue #373 changes that: Robolectric runs the Android framework on the JVM, so a
+//     `createComposeRule()` test in the `test` source set now gives these files real JVM coverage
+//     without an emulator. This bucket therefore SHRINKS one screen at a time — each glob is deleted
+//     in the same PR that adds that screen's Robolectric JVM Compose test. AddAnotherAccountScreen was
+//     the first (see AddAnotherAccountScreenJvmTest) and has been removed below; the rest are tracked
+//     as per-area conversion tickets under #373. The coverage-floor re-ratchet is deferred until the
+//     whole conversion is done and stable (#373) — do NOT raise it in a conversion PR.
 //  2. Android framework entry points the OS instantiates directly (Activity/Service/Application/
 //     BackupAgent) rather than the app's own code constructing them.
 //  3. Hilt DI modules — `@Provides`/`@Binds` one-liners with no branching logic.
@@ -298,7 +311,7 @@ val jacocoNonJvmTestableSurface = listOf(
     "**/AppLockGateHost*",
     "**/FolderDrawer*",
     "**/MailboxScreen*",
-    "**/AddAnotherAccountScreen*",
+    // AddAnotherAccountScreen converted to a Robolectric JVM Compose test (#373) — now JVM-covered.
     "**/BatteryOptimizationScreen*",
     "**/ContactsAccessScreen*",
     "**/LicenseScreen*",
@@ -399,6 +412,45 @@ tasks.named("check") {
     dependsOn("jacocoTestCoverageVerification")
 }
 
+// --- Robolectric android-all offline resolution (issue #373) ------------------------------------
+// Robolectric runs the real Android framework on the JVM from a large `android-all-instrumented`
+// jar. By default it resolves that jar LAZILY AT TEST TIME by downloading it from Maven Central
+// (org.robolectric.internal.dependency.MavenDependencyResolver -> MavenArtifactFetcher). That
+// runtime download is unreliable on CI runners and failed the JVM Compose PoC in CI with
+// `java.lang.AssertionError at MavenArtifactFetcher ... Caused by: java.io.IOException` ("Failed to
+// fetch maven artifact"). Fix: resolve the jar through Gradle instead — reliable, cached, and
+// persisted by the CI Gradle cache, using the same repositories as every other dependency — then
+// hand it to Robolectric in OFFLINE mode so it never touches the network at test time.
+//
+// A DEDICATED resolvable configuration (deliberately NOT testImplementation/testRuntimeOnly) keeps
+// the ~200 MB instrumented framework jar OFF the JVM unit-test classpath: it must be loaded only by
+// Robolectric's sandbox classloader, never flattened onto the app's test classpath where it would
+// collide with the stub `android.jar`. `syncRobolectricAndroidAll` stages the resolved jar under
+// its Maven filename (android-all-instrumented-<version>.jar) — exactly what Robolectric's
+// LocalDependencyResolver looks up as <artifactId>-<version>.jar — and the two system properties
+// below switch Robolectric onto that offline directory (see LegacyDependencyResolver). Every
+// Robolectric test pins @Config(sdk = 36) (app/src/test/resources/robolectric.properties), so the
+// single sdk=36 jar covers them all; a test on a different SDK must add that android-all version to
+// this configuration too. The offline properties are inert for non-Robolectric JVM tests.
+val robolectricAndroidAll: Configuration = configurations.create("robolectricAndroidAll") {
+    isCanBeConsumed = false
+    isCanBeResolved = true
+}
+
+val robolectricDepsDir = layout.buildDirectory.dir("robolectric-android-all")
+
+val syncRobolectricAndroidAll = tasks.register<Sync>("syncRobolectricAndroidAll") {
+    description = "Stages Robolectric's android-all-instrumented jar for offline resolution (issue #373)."
+    from(robolectricAndroidAll)
+    into(robolectricDepsDir)
+}
+
+tasks.withType<Test>().configureEach {
+    dependsOn(syncRobolectricAndroidAll)
+    systemProperty("robolectric.offline", "true")
+    systemProperty("robolectric.dependency.dir", robolectricDepsDir.get().asFile.absolutePath)
+}
+
 dependencies {
     implementation(libs.androidx.core.ktx)
     implementation(libs.androidx.lifecycle.runtime.ktx)
@@ -459,6 +511,24 @@ dependencies {
     // The real org.json for unit tests (android.jar ships a stubbed, no-op version).
     testImplementation("org.json:json:20231013")
 
+    // Robolectric-backed JVM Compose UI tests (issue #373): Robolectric runs the Android framework
+    // on the JVM so `createComposeRule()` can drive composables without an emulator, bringing screen
+    // render code into the JaCoCo JVM-testable surface. The Compose test artifacts come from the same
+    // BOM as the app (aligned versions) and reuse the ui-test-junit4 / ui-test-manifest aliases the
+    // androidTest source set already declares — here in `test` (JVM), not `androidTest`. Robolectric
+    // sources Android's real org.json from its sandbox, so it does not clash with the stub-replacing
+    // org.json above (that is for the plain, non-Robolectric JVM tests).
+    testImplementation(libs.robolectric)
+    // The android-all-instrumented framework jar Robolectric loads into its sandbox — resolved via
+    // Gradle and staged for offline use by syncRobolectricAndroidAll above so no flaky test-time
+    // download happens in CI (issue #373). On its own dedicated configuration, NOT the test
+    // classpath — see that block for why. The artifact has no transitive dependencies (verified from
+    // its POM), so it resolves to exactly the one staged jar.
+    "robolectricAndroidAll"(libs.robolectric.android.all.instrumented)
+    testImplementation(platform(libs.androidx.compose.bom))
+    testImplementation(libs.androidx.compose.ui.test.junit4)
+    testImplementation(libs.androidx.compose.ui.test.manifest)
+
     androidTestImplementation(libs.androidx.junit)
     androidTestImplementation(libs.androidx.espresso.core)
     androidTestImplementation(libs.androidx.espresso.intents)

app/src/test/kotlin/org/libremail/ui/onboarding/AddAnotherAccountScreenJvmTest.kt

@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+package org.libremail.ui.onboarding
+
+import android.content.Context
+import androidx.compose.ui.test.assertIsDisplayed
+import androidx.compose.ui.test.junit4.v2.createComposeRule
+import androidx.compose.ui.test.onNodeWithText
+import androidx.compose.ui.test.performClick
+import org.junit.Assert.assertTrue
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.libremail.R
+import org.libremail.ui.theme.LibreMailTheme
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.RuntimeEnvironment
+import org.robolectric.annotation.Config
+import org.robolectric.annotation.GraphicsMode
+
+/**
+ * Robolectric feasibility PoC (issue #373): proves Jetpack Compose UI can be unit-tested on the JVM
+ * without an emulator. `createComposeRule()` drives [AddAnotherAccountScreen] under
+ * [RobolectricTestRunner]; `stringResource(...)` and Material3 theming resolve because
+ * `testOptions.unitTests.isIncludeAndroidResources` is enabled in `app/build.gradle.kts`. Runs under
+ * `:app:testDebugUnitTest`, NOT `androidTest` — the instrumented `AddAnotherAccountScreenTest` stays.
+ *
+ * `@Config(sdk = [36])` because compileSdk/targetSdk 37 (preview) has no Robolectric 4.16 sandbox
+ * (also the default in `src/test/resources/robolectric.properties`); `@GraphicsMode(NATIVE)` is
+ * required for Compose to render under Robolectric.
+ */
+@RunWith(RobolectricTestRunner::class)
+@GraphicsMode(GraphicsMode.Mode.NATIVE)
+@Config(sdk = [36])
+class AddAnotherAccountScreenJvmTest {
+
+    @get:Rule
+    val composeTestRule = createComposeRule()
+
+    private val context: Context get() = RuntimeEnvironment.getApplication()
+
+    private fun string(resId: Int): String = context.getString(resId)
+
+    private fun setContent(onAddAnother: () -> Unit = {}, onFinish: () -> Unit = {}) {
+        composeTestRule.setContent {
+            LibreMailTheme(darkTheme = false, dynamicColor = false) {
+                AddAnotherAccountScreen(onAddAnother = onAddAnother, onFinish = onFinish)
+            }
+        }
+    }
+
+    @Test
+    fun rendersAccountAddedTitleFromResources() {
+        setContent()
+
+        // Proves the merged Android resource table loaded on the JVM (isIncludeAndroidResources).
+        composeTestRule.onNodeWithText(string(R.string.onboarding_account_added_title)).assertIsDisplayed()
+    }
+
+    @Test
+    fun tappingYes_invokesOnAddAnother() {
+        var addAnother = false
+        setContent(onAddAnother = { addAnother = true })
+
+        composeTestRule.onNodeWithText(string(R.string.onboarding_add_another_yes)).performClick()
+
+        assertTrue(addAnother)
+    }
+
+    @Test
+    fun tappingNo_invokesOnFinish() {
+        var finished = false
+        setContent(onFinish = { finished = true })
+
+        composeTestRule.onNodeWithText(string(R.string.onboarding_add_another_no)).performClick()
+
+        assertTrue(finished)
+    }
+}

app/src/test/resources/robolectric.properties

@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+# Default SDK for every Robolectric (JVM) test (issue #373). compileSdk/targetSdk are 37, a
+# preview level Robolectric 4.16.x does not ship a sandbox for; 36 (Baklava) is its newest
+# supported level and needs JDK 21 (the project's Gradle JDK). Individual tests may still override
+# with @Config(sdk = [..]). Only affects tests run with RobolectricTestRunner; plain JUnit unit
+# tests are unaffected.
+sdk=36

gradle/libs.versions.toml

@@ -30,6 +30,22 @@ androidxTestRules = "1.7.0"
 turbine = "1.2.1"
 mockk = "1.14.11"
 greenmail = "2.1.9"
+# Robolectric — runs the Android framework on the JVM so Compose UI (createComposeRule) can be
+# unit-tested without an emulator (issue #373). 4.16.x is the first line to support compileSdk 36
+# (Baklava) and requires JDK 21 for it; API 37 (preview) is unsupported, so Robolectric tests pin
+# @Config(sdk = 36) — also set in app/src/test/resources/robolectric.properties.
+robolectric = "4.16.1"
+# The instrumented android-all runtime jar Robolectric loads into its sandbox to run the Android
+# framework on the JVM. By DEFAULT Robolectric downloads this ~200 MB artifact from Maven Central
+# lazily at TEST time (MavenDependencyResolver -> MavenArtifactFetcher); that runtime fetch is
+# unreliable on CI runners and failed the JVM Compose PoC with "Failed to fetch maven artifact"
+# (issue #373). Pinning it lets Gradle resolve+cache it and hand it to Robolectric in offline mode
+# (see the robolectricAndroidAll wiring in app/build.gradle.kts) so no network fetch happens at
+# test time. The value is BOTH Robolectric-version- and SDK-specific: it is exactly what
+# Robolectric 4.16.1's DefaultSdkProvider maps @Config(sdk = 36) to — androidVersion "16", build
+# "13921718", preinstrumented suffix "-i7". Bump it together with `robolectric` above, and update
+# it if the pinned @Config(sdk = ..) / robolectric.properties SDK ever changes.
+robolectricAndroidAll = "16-robolectric-13921718-i7"
 errorprone = "2.50.0"
 # Lint/format. ktlint owns formatting; detekt owns static analysis (formatting ruleset off).
 # detekt 2.0 is the only line with Gradle 9 support (stable 1.23.x tops out at Gradle 8.12).
@@ -115,6 +131,11 @@ mockk = { group = "io.mockk", name = "mockk", version.ref = "mockk" }
 # mockk's Android artifact for instrumented tests (dexmaker/byte-buddy-android backed).
 mockk-android = { group = "io.mockk", name = "mockk-android", version.ref = "mockk" }
 greenmail = { group = "com.icegreen", name = "greenmail", version.ref = "greenmail" }
+# Robolectric — JVM Android framework for unit-testing Compose UI without an emulator (issue #373).
+robolectric = { group = "org.robolectric", name = "robolectric", version.ref = "robolectric" }
+# Resolved via Gradle (not Robolectric's runtime Maven fetch) and staged for offline use so the JVM
+# Compose tests run in CI without a flaky test-time download — see app/build.gradle.kts (issue #373).
+robolectric-android-all-instrumented = { group = "org.robolectric", name = "android-all-instrumented", version.ref = "robolectricAndroidAll" }
 androidx-junit = { group = "androidx.test.ext", name = "junit", version.ref = "androidxJunit" }
 androidx-espresso-core = { group = "androidx.test.espresso", name = "espresso-core", version.ref = "espresso" }
 androidx-espresso-intents = { group = "androidx.test.espresso", name = "espresso-intents", version.ref = "espresso" }