Android instrumentation test doesn't run to end when using Room @Transaction function

Question

I\'m testing with AS 3.4.1 and Emulator running Android 9.

The following test won\'t run, when I use a Room Dao Function annotated with @Transaction in

Answer 1

I faced the same issue and the problem was because of the InstantTaskExecutorRule, if you remove the below block of code the @Transaction should work fine with the suspend keyword

@Rule
@JvmField
val instantTaskExecutorRule = InstantTaskExecutorRule()

It seems that this rule blocks the RoomDatabase from acquiring the transaction thread. In RoomDatabase.kt execution gets blocked in the below function:

private suspend fun Executor.acquireTransactionThread(controlJob: Job): ContinuationInterceptor

Hope this helps!

Answer 2

You can use setTransactionExecutor to run transaction in another thread

return Room
       .inMemoryDatabaseBuilder(context, MyRoomDatabase::class.java)
       .setTransactionExecutor(Executors.newSingleThreadExecutor())
       .build()

then while testing use runBlocking instead of runBlockingTest

@Test
fun moveItem() = runBlocking {
    transactionFunction()
}