房间本地单元测试 - 从 DataSource.Factory 查询 PagedList
[英]Room Local Unit Test - Query PagedList from DataSource.Factory
问题描述
Issue
问题
Expected预期的
Using a JUnit 5 local unit test, run a Room database @Insert and Query within a TestCoroutineDispatcher() .使用 JUnit 5 本地单元测试，在TestCoroutineDispatcher()中运行 Room 数据库@Insert和Query 。
Observed观察到的
The Room database @Insert and @Query is executed within TestCoroutineDispatcher().runBlockingTest , causing the error below. Room 数据库@Insert和@Query在TestCoroutineDispatcher().runBlockingTest中执行，导致以下错误。 The database calls will work if the threading is explicitly defined with the non-test dispatcher, Dispatchers.IO .如果使用非测试调度程序Dispatchers.IO显式定义线程，则数据库调用将起作用。
Error log:错误日志：
Cannot access database on the main thread since it may potentially lock the UI for a long period of time.
Implement实施
1. Add libraries 1.添加库
- JUnit 5: Setup JUnit 5：设置
- Robolectric: Getting Started Robolectric：入门
- AndroidX: Set up project for AndroidX Test > List of AndroidX Test dependencies AndroidX：为 AndroidX 测试设置项目 > AndroidX 测试依赖项列表
- Kotlin coroutines: Using in your project Kotlin 协程： 在您的项目中使用
build.gradle (SomeProjectName) build.gradle (SomeProjectName)
dependencies {
...
// JUnit 5
classpath("de.mannodermaus.gradle.plugins:android-junit5:X.X.X")
}
build.gradle (:someModuleName) build.gradle (:someModuleName)
apply plugin: "de.mannodermaus.android-junit5"
// JUnit 5
testImplementation "org.junit.jupiter:junit-jupiter-api:X.X.X"
testRuntimeOnly "org.junit.jupiter:junit-jupiter-engine:X.X.X"
// Robolectric
testImplementation "org.robolectric:robolectric:X.X.X"
testImplementation "androidx.test.ext:junit:X.X.X"
testImplementation "org.jetbrains.kotlinx:kotlinx-coroutines-test:X.X.X"
2. Create test 2.创建测试
a.一个。 Set test Dispatcher and LiveData executor.设置测试 Dispatcher 和 LiveData 执行器。
b.湾。 Create a test database: Test and debug your database .创建测试数据库： 测试和调试您的数据库。
c. c。 Ensure the test database executes on the same Dispatcher as the unit test: Testing AndroidX Room + Kotlin Coroutines - @Eyal Guthmann确保测试数据库在与单元测试相同的 Dispatcher 上执行： Testing AndroidX Room + Kotlin Coroutines - @Eyal Guthmann
d. d。 Run the database @Insert and @Query within TestCoroutineDispatcher().runBlockingTest .在TestCoroutineDispatcher().runBlockingTest中运行数据库@Insert和@Query 。
SomeTest.kt SomeTest.kt
import androidx.test.core.app.ApplicationProvider
@ExperimentalCoroutinesApi
@Config(maxSdk = Build.VERSION_CODES.P, minSdk = Build.VERSION_CODES.P)
@RunWith(RobolectricTestRunner::class)
class SomeTest {
private val testDispatcher = TestCoroutineDispatcher()
@Test
fun someTest() = testDispatcher.runBlockingTest {
// Test setup, moved to test extension in production. Also, cleanup methods not included here for simplicity.
// Set Coroutine Dispatcher.
Dispatchers.setMain(testDispatcher)
// Set LiveData Executor.
ArchTaskExecutor.getInstance().setDelegate(object : TaskExecutor() {
override fun executeOnDiskIO(runnable: Runnable) = runnable.run()
override fun postToMainThread(runnable: Runnable) = runnable.run()
override fun isMainThread(): Boolean = true
})
val appContext = ApplicationProvider.getApplicationContext<Context>()
// Room database setup
db = Room.inMemoryDatabaseBuilder(appContext, SomeDatabase::class.java)
.setTransactionExecutor(testDispatcher.asExecutor())
.setQueryExecutor(testDispatcher.asExecutor())
.build()
dao = db.someDao()
// Insert into database.
dao.insertData(mockDataList)
// Query database.
val someQuery = dao.queryData().toLiveData(PAGE_SIZE).asFlow()
someQuery.collect {
// TODO: Test something here.
}
// TODO: Make test assertions.
...
}
SomeDao.kt SomeDao.kt
@Dao
interface SomeDao {
@Insert(onConflict = OnConflictStrategy.IGNORE)
suspend fun insertData(data: List<SomeData>)
@Query("SELECT * FROM someDataTable")
fun queryData(): DataSource.Factory<Int, SomeData>
}
Attempted solutions尝试的解决方案
1. Add suspend modifier to SomeDao.kt 's queryData function. 1. 在SomeDao.kt的queryData function 中添加suspend修饰符。
After adding suspend , the methods that subsequently call queryData must either implement suspend as well or be launched using launch , from a coroutine, as shown below.添加suspend之后，随后调用queryData的方法必须要么实现suspend ，要么使用launch ，从协程启动，如下所示。
This results in an error from the compiler.这会导致编译器出错。
error: Not sure how to convert a Cursor to this method's return type (androidx.paging.DataSource.Factory<{SomeDataClassPathHere}>).
SomeDao.kt SomeDao.kt
@Dao
interface SomeDao {
...
@Query("SELECT * FROM someDataTable")
suspend fun queryData(): DataSource.Factory<Int, SomeData>
}
SomeRepo.kt SomeRepo.kt
suspend fun getInitialData(pagedListBoundaryCallback: PagedList.BoundaryCallback<SomeData>) = flow {
emit(Resource.loading(null))
try {
dao.insertData(getDataRequest(...))
someDataQuery(pagedListBoundaryCallback).collect {
emit(Resource.success(it))
}
} catch (error: Exception) {
someDataQuery(pagedListBoundaryCallback).collect {
emit(Resource.error(error.localizedMessage!!, it))
}
}
}
SomeViewModel.kt SomeViewModel.kt
private suspend fun loadNetwork(toRetry: Boolean) {
repository.getInitialData(pagedListBoundaryCallback(toRetry)).onEach {
when (it.status) {
LOADING -> _viewState.value = ...
SUCCESS -> _viewState.value = ...
ERROR -> _viewState.value = ...
}
}.flowOn(coroutineDispatcherProvider.io()).launchIn(coroutineScope)
}
fun bindIntents(view: FeedView) {
view.loadNetworkIntent().onEach {
coroutineScope.launch(coroutineDispatcherProvider.io()) {
loadNetwork(it.toRetry)
}
}.launchIn(coroutineScope)
}
private fun pagedListBoundaryCallback(toRetry: Boolean) =
object : PagedList.BoundaryCallback<SomeData>() {
override fun onZeroItemsLoaded() {
super.onZeroItemsLoaded()
if (toRetry) {
coroutineScope.launch(coroutineDispatcherProvider.io()) {
loadNetwork(false)
}
}
}
2. Run the test with TestCoroutineScope . 2. 使用TestCoroutineScope运行测试。
SomeTest.kt SomeTest.kt
@ExperimentalCoroutinesApi
@Config(maxSdk = Build.VERSION_CODES.P, minSdk = Build.VERSION_CODES.P)
@RunWith(RobolectricTestRunner::class)
class SomeTest {
private val testDispatcher = TestCoroutineDispatcher()
private val testScope = TestCoroutineScope(testDispatcher)
@Test
fun someTest() = testScope.runBlockingTest {
...
}
3. Run the test with runBlockingTest . 3. 使用runBlockingTest运行测试。
@Test
fun someTest() = runBlockingTest {
...
}
4. Launch the Room calls using TestCoroutineScope on TestCoroutineDispatcher. 4. 使用 TestCoroutineDispatcher 上的 TestCoroutineScope 启动 Room 调用。
This doesn't cause a main thread error.这不会导致主线程错误。 However, the Room calls do not work with this method.但是，房间调用不适用于此方法。
@Test
fun topCafesTest() = testDispatcher.runBlockingTest {
testScope.launch(testDispatcher) {
dao.insertCafes(mockCafesList)
val cafesQuery = dao.queryCafes().toLiveData(PAGE_SIZE).asFlow()
cafesQuery.collect {
...
}
}
}
Full error log完整的错误日志
java.lang.IllegalStateException: Cannot access database on the main thread since it may potentially lock the UI for a long period of time.
at androidx.room.RoomDatabase.assertNotMainThread(RoomDatabase.java:267) at androidx.room.RoomDatabase.beginTransaction(RoomDatabase.java:351) at app.topcafes.feed.database.FeedDao_Impl$2.call(FeedDao_Impl.java:91) at app.topcafes.feed.database.FeedDao_Impl$2.call(FeedDao_Impl.java:88) at androidx.room.CoroutinesRoom$Companion$execute$2.invokeSuspend(CoroutinesRoom.kt:54) at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33) at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:56) at androidx.room.TransactionExecutor$1.run(TransactionExecutor.java:45) at kotlinx.coroutines.test.TestCoroutineDispatcher.dispatch(TestCoroutineDispatcher.kt:50) at kotlinx.coroutines.DispatcherExecutor.execute(Executors.kt:62) at androidx.room.TransactionExecut
1 个解决方案
解决方案1
2 已采纳 2020-06-15 00:01:05
Run Room @Insert and @Query on Dispatchers.IO在Dispatchers.IO上运行 Room @Insert和@Query
SomeTest.kt SomeTest.kt
@ExperimentalCoroutinesApi
@Config(maxSdk = Build.VERSION_CODES.P, minSdk = Build.VERSION_CODES.P)
@RunWith(RobolectricTestRunner::class)
class SomeTest {
private val testDispatcher = TestCoroutineDispatcher()
private val testScope = TestCoroutineScope(testDispatcher)
@Test
fun someTest() = testDispatcher.runBlockingTest {
// Same Dispatcher, LiveData, and Room setup used as defined in the question above.
testScope.launch(Dispatchers.IO) {
// Insert into database.
dao.insertData(mockDataList)
// Query database.
val someQuery = dao.queryData().toLiveData(PAGE_SIZE).asFlow()
someQuery.collect {
// TODO: Test something here.
}
}
// TODO: Make test assertions.
...
}
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