Minor tidy ups (#935)

* Add suspend to upsertAll * withContext only wraps mapping functions * Remove main coroutine rule from TaskDaoTest * Rename tasksRepository to taskRepository * Replace MainCoroutineRule with testScope and testDispatcher * Fix spotless * All tests run with testScope.runTest * Add mutex to TaskNetworkDataSource * Fix spotless * Recreate database before each test
android · Apr 3, 2023 · d7ba290 · d7ba290
1 parent 4aff247
commit d7ba290
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Showing 6 changed files with 87 additions and 107 deletions.
diff --git a/...java/com/example/android/architecture/blueprints/todoapp/data/source/local/TaskDaoTest.kt b/...java/com/example/android/architecture/blueprints/todoapp/data/source/local/TaskDaoTest.kt
@@ -20,13 +20,11 @@ import androidx.room.Room
 import androidx.test.core.app.ApplicationProvider.getApplicationContext
 import androidx.test.ext.junit.runners.AndroidJUnit4
 import androidx.test.filters.SmallTest
-import com.example.android.architecture.blueprints.todoapp.MainCoroutineRule
 import junit.framework.TestCase.assertEquals
 import junit.framework.TestCase.assertNotNull
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.test.runTest
 import org.junit.Before
-import org.junit.Rule
 import org.junit.Test
 import org.junit.runner.RunWith
 
@@ -37,19 +35,16 @@ class TaskDaoTest {
 
     // using an in-memory database because the information stored here disappears when the
     // process is killed
-    private val database = Room.inMemoryDatabaseBuilder(
-        getApplicationContext(),
-        ToDoDatabase::class.java
-    ).allowMainThreadQueries().build()
+    private lateinit var database: ToDoDatabase
 
-    // Set the main coroutines dispatcher for unit testing.
-    @get:Rule
-    val mainCoroutineRule = MainCoroutineRule()
-
-    // Ensure that we use an empty database for each test.
+    // Ensure that we use a new database for each test.
     @Before
-    fun initDb() = database.clearAllTables()
-
+    fun initDb() {
+        database = Room.inMemoryDatabaseBuilder(
+            getApplicationContext(),
+            ToDoDatabase::class.java
+        ).allowMainThreadQueries().build()
+    }
     @Test
     fun insertTaskAndGetById() = runTest {
         // GIVEN - insert a task

diff --git a/...in/java/com/example/android/architecture/blueprints/todoapp/data/DefaultTaskRepository.kt b/...in/java/com/example/android/architecture/blueprints/todoapp/data/DefaultTaskRepository.kt
@@ -174,7 +174,10 @@ class DefaultTaskRepository @Inject constructor(
         scope.launch {
             try {
                 val localTasks = localDataSource.getAll()
-                networkDataSource.saveTasks(localTasks.toNetwork())
+                val networkTasks = withContext(dispatcher) {
+                    localTasks.toNetwork()
+                }
+                networkDataSource.saveTasks(networkTasks)
             } catch (e: Exception) {
                 // In a real app you'd handle the exception e.g. by exposing a `networkStatus` flow
                 // to an app level UI state holder which could then display a Toast message.

diff --git a/...ain/java/com/example/android/architecture/blueprints/todoapp/data/source/local/TaskDao.kt b/...ain/java/com/example/android/architecture/blueprints/todoapp/data/source/local/TaskDao.kt
@@ -75,7 +75,7 @@ interface TaskDao {
      * @param tasks the tasks to be inserted or updated.
      */
     @Upsert
-    fun upsertAll(tasks: List<LocalTask>)
+    suspend fun upsertAll(tasks: List<LocalTask>)
 
     /**
      * Update the complete status of a task

diff --git a/...mple/android/architecture/blueprints/todoapp/data/source/network/TaskNetworkDataSource.kt b/...mple/android/architecture/blueprints/todoapp/data/source/network/TaskNetworkDataSource.kt
@@ -18,46 +18,35 @@ package com.example.android.architecture.blueprints.todoapp.data.source.network
 
 import javax.inject.Inject
 import kotlinx.coroutines.delay
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
 
-/**
- * Implementation of the data source that adds a latency simulating network.
- *
- */
 class TaskNetworkDataSource @Inject constructor() : NetworkDataSource {
 
-    private val SERVICE_LATENCY_IN_MILLIS = 2000L
-
-    private var TASK_SERVICE_DATA = LinkedHashMap<String, NetworkTask>(2)
-
-    init {
-        addTask(
+    // A mutex is used to ensure that reads and writes are thread-safe.
+    private val accessMutex = Mutex()
+    private var tasks = listOf(
+        NetworkTask(
             id = "PISA",
             title = "Build tower in Pisa",
             shortDescription = "Ground looks good, no foundation work required."
-        )
-        addTask(
+        ),
+        NetworkTask(
             id = "TACOMA",
             title = "Finish bridge in Tacoma",
             shortDescription = "Found awesome girders at half the cost!"
         )
-    }
+    )
 
-    override suspend fun loadTasks(): List<NetworkTask> {
-        // Simulate network by delaying the execution.
-        val tasks = TASK_SERVICE_DATA.values.toList()
+    override suspend fun loadTasks(): List<NetworkTask> = accessMutex.withLock {
         delay(SERVICE_LATENCY_IN_MILLIS)
         return tasks
     }
 
-    override suspend fun saveTasks(tasks: List<NetworkTask>) {
-        // Simulate network by delaying the execution.
+    override suspend fun saveTasks(newTasks: List<NetworkTask>) = accessMutex.withLock {
         delay(SERVICE_LATENCY_IN_MILLIS)
-        TASK_SERVICE_DATA.clear()
-        TASK_SERVICE_DATA.putAll(tasks.associateBy(NetworkTask::id))
-    }
-
-    private fun addTask(id: String, title: String, shortDescription: String) {
-        val newTask = NetworkTask(id = id, title = title, shortDescription = shortDescription)
-        TASK_SERVICE_DATA[newTask.id] = newTask
+        tasks = newTasks
     }
 }
+
+private const val SERVICE_LATENCY_IN_MILLIS = 2000L