Android 检测测试在测试使用 RoomDatabase.withTransaction 的挂起函数时卡住

Question

我正在尝试测试以下 LocalDataSource 函数， NameLocalData.methodThatFreezes 功能，但它卡住。我该如何解决这个问题？或者我该如何以另一种方式对其进行测试？

待测类

class NameLocalData(private val roomDatabase: RoomDatabase) : NameLocalDataSource {

  override suspend fun methodThatFreezes(someParameter: Something): Something {
    roomDatabase.withTransaction {
      try {
        // calling room DAO methods here
      } catch(e: SQLiteConstraintException) {
        // ...
      }
      return something
    }
  }
}

测试类

@MediumTest
@RunWith(AndroidJUnit4::class)
class NameLocalDataTest {
  private lateinit var nameLocalData: NameLocalData

  // creates a Room database in memory
  @get:Rule
  var roomDatabaseRule = RoomDatabaseRule()

  @get:Rule
  var instantTaskExecutorRule = InstantTaskExecutorRule()

  @Before
  fun setup() = runBlockingTest {
     initializesSomeData()
     nameLocalData = NameLocalData(roomDatabaseRule.db)
  }

 @Test
 fun methodThatFreezes() = runBlockingTest {
    nameLocalData.methodThatFreezes // test freezes
 }

 // ... others NameLocalDataTest tests where those functions been tested does not use
 // roomDatabase.withTransaction { } 
}

Gradle 的文件配置

espresso_version = '3.2.0'
kotlin_coroutines_version = '1.3.3'
room_version = '2.2.5'

test_arch_core_testing = '2.1.0'
test_ext_junit_version = '1.1.1'
test_roboletric = '4.3.1'
test_runner_version = '1.2.0'

androidTestImplementation "androidx.arch.core:core-testing:$test_arch_core_testing"
androidTestImplementation "androidx.test.espresso:espresso-core:$espresso_version"
androidTestImplementation "androidx.test.ext:junit:$test_ext_junit_version"
androidTestImplementation "androidx.test:rules:$test_runner_version"
androidTestImplementation "androidx.test:runner:$test_runner_version"
androidTestImplementation "org.jetbrains.kotlinx:kotlinx-coroutines-test:$kotlin_coroutines_version"

Answer 1

上次我为 Room 数据库编写测试时，我只是简单地使用了 runBlock它对我有用......
你能看看this sample并检查它是否也适合您？

编辑:
行动!我错过了这部分......我试过这个(在同一个样本中):

我使用 @Transaction 在我的 DAO 中定义了一个虚拟函数

@Transaction
suspend fun quickInsert(book: Book) {
    save(book)
    delete(book)
}

我认为这是问题的关键。添加 setTransactionExecutor到您的数据库实例化。

appDatabase = Room.inMemoryDatabaseBuilder(
    InstrumentationRegistry.getInstrumentation().context,
    AppDatabase::class.java
).setTransactionExecutor(Executors.newSingleThreadExecutor())
    .build()

最后，使用 runBlocking 进行测试。

@Test
fun dummyTest() = runBlocking {
    val dao = appDatabase.bookDao();
    val id = dummyBook.id

    dao.quickInsert(dummyBook)

    val book = dao.bookById(id).first()
    assertNull(book)
}

见 this question .