test(conversations): cover the periodic conversation sync worker

What is worth pinning down about a background worker is when it stands
down and how many accounts it touches when it does not: a guard that
quietly stops working is invisible until it turns up as battery drain or
request volume, long after the change that broke it.

Covers battery saver standing the run down without reading a single
account, every configured account being synced rather than only the
current one, a failed account asking for another attempt while its
neighbours still sync, the attempt cap ending the retries, and an
account lookup that throws being survivable.

Unit tests gain the WorkManager testing artifact, which was available to
instrumented tests only.

Assisted-by: Claude Code:claude-opus-5
Signed-off-by: Andy Scherzinger <info@andy-scherzinger.de>

Author: AndyScherzinger

app/build.gradle.kts

@@ -372,6 +372,7 @@ dependencies {
     androidTestImplementation("org.jetbrains.kotlinx:kotlinx-coroutines-test:1.11.0")
     androidTestImplementation("androidx.test:core-ktx:1.7.0")
     androidTestImplementation("org.mockito:mockito-android:5.22.0")
+    testImplementation("androidx.work:work-testing:$workVersion")
     androidTestImplementation("androidx.work:work-testing:$workVersion")
     androidTestImplementation("androidx.test.espresso:espresso-core:$espressoVersion") {
         exclude(group = "com.android.support", module = "support-annotations")

app/src/test/java/com/nextcloud/talk/jobs/ConversationsSyncWorkerTest.kt

@@ -0,0 +1,136 @@
+/*
+ * Nextcloud Talk - Android Client
+ *
+ * SPDX-FileCopyrightText: 2026 Andy Scherzinger <andy.scherzinger@nextcloud.com>
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+package com.nextcloud.talk.jobs
+
+import android.app.Application
+import android.content.Context
+import android.os.PowerManager
+import androidx.test.core.app.ApplicationProvider
+import androidx.work.ListenableWorker
+import androidx.work.testing.TestListenableWorkerBuilder
+import com.nextcloud.talk.conversationlist.data.OfflineConversationsRepository
+import com.nextcloud.talk.data.user.model.User
+import com.nextcloud.talk.users.UserManager
+import io.reactivex.Single
+import kotlinx.coroutines.runBlocking
+import org.junit.Assert.assertEquals
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.mockito.kotlin.any
+import org.mockito.kotlin.mock
+import org.mockito.kotlin.never
+import org.mockito.kotlin.verify
+import org.mockito.kotlin.verifyBlocking
+import org.mockito.kotlin.whenever
+import org.mockito.kotlin.wheneverBlocking
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.Shadows.shadowOf
+import org.robolectric.annotation.Config
+
+/**
+ * Tests for [ConversationsSyncWorker]: which accounts a run syncs, when a run stands down without
+ * syncing, and how a failed run reports itself.
+ */
+@RunWith(RobolectricTestRunner::class)
+@Config(application = Application::class, sdk = [33])
+class ConversationsSyncWorkerTest {
+
+    private val userManager: UserManager = mock()
+    private val repository: OfflineConversationsRepository = mock()
+
+    @Test
+    fun `every account is synced, not just the current one`() {
+        val worker = worker()
+        whenever(userManager.users).thenReturn(Single.just(listOf(user(1), user(2), user(3))))
+        wheneverBlocking { repository.syncRooms(any(), any()) }.thenReturn(true)
+
+        val result = runBlocking { worker.sync() }
+
+        assertEquals(ListenableWorker.Result.success(), result)
+        verifyBlocking(repository) { syncRooms(user(1), false) }
+        verifyBlocking(repository) { syncRooms(user(2), false) }
+        verifyBlocking(repository) { syncRooms(user(3), false) }
+    }
+
+    @Test
+    fun `battery saver stands the sync down entirely`() {
+        val worker = worker()
+        shadowOf(applicationContext().getSystemService(Context.POWER_SERVICE) as PowerManager)
+            .setIsPowerSaveMode(true)
+
+        val result = runBlocking { worker.sync() }
+
+        assertEquals(ListenableWorker.Result.success(), result)
+        verify(userManager, never()).users
+        verifyBlocking(repository, never()) { syncRooms(any(), any()) }
+    }
+
+    @Test
+    fun `an account with nothing to sync is not an error`() {
+        val worker = worker()
+        whenever(userManager.users).thenReturn(Single.just(emptyList()))
+
+        val result = runBlocking { worker.sync() }
+
+        assertEquals(ListenableWorker.Result.success(), result)
+        verifyBlocking(repository, never()) { syncRooms(any(), any()) }
+    }
+
+    @Test
+    fun `a failed account asks for another attempt`() {
+        val worker = worker(runAttempt = 0)
+        whenever(userManager.users).thenReturn(Single.just(listOf(user(1), user(2))))
+        wheneverBlocking { repository.syncRooms(user(1), false) }.thenReturn(true)
+        wheneverBlocking { repository.syncRooms(user(2), false) }.thenReturn(false)
+
+        val result = runBlocking { worker.sync() }
+
+        assertEquals(ListenableWorker.Result.retry(), result)
+        // the account that did sync was still synced, rather than abandoned with its neighbour
+        verifyBlocking(repository) { syncRooms(user(1), false) }
+    }
+
+    @Test
+    fun `a sync that keeps failing gives up instead of retrying for ever`() {
+        val worker = worker(runAttempt = 2)
+        whenever(userManager.users).thenReturn(Single.just(listOf(user(1))))
+        wheneverBlocking { repository.syncRooms(any(), any()) }.thenReturn(false)
+
+        val result = runBlocking { worker.sync() }
+
+        assertEquals(ListenableWorker.Result.failure(), result)
+    }
+
+    @Test
+    fun `an account whose lookup throws does not take the other accounts down with it`() {
+        val worker = worker()
+        whenever(userManager.users).thenReturn(Single.error(IllegalStateException("database is gone")))
+
+        val result = runBlocking { worker.sync() }
+
+        assertEquals(ListenableWorker.Result.success(), result)
+        verifyBlocking(repository, never()) { syncRooms(any(), any()) }
+    }
+
+    private fun worker(runAttempt: Int = 0): ConversationsSyncWorker =
+        TestListenableWorkerBuilder<ConversationsSyncWorker>(applicationContext())
+            .setRunAttemptCount(runAttempt)
+            .build()
+            .also {
+                it.userManager = userManager
+                it.conversationsRepository = repository
+            }
+
+    private fun applicationContext(): Context = ApplicationProvider.getApplicationContext()
+
+    private fun user(id: Long): User = User(id = id, userId = "user$id", username = "user$id", baseUrl = BASE_URL)
+
+    companion object {
+        private const val BASE_URL = "https://server.example.com"
+    }
+}