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 it.

class RecurrenceManagerTest : DatabaseTest() {

    @Rule
    @JvmField
    val instantTaskExecutorRule = InstantTaskExecutorRule()

    var recurringEntryId: Long = -1

    @Before
    override fun setup() {
        super.setup() // only initialized the db

        val recurringEntry = RecurringEntry(
            recurrence = Recurrence(DATE.toEpochMilli(), Recurrence.DAILY)
        )

        recurringEntryId = runBlocking { db.recurringEntryDao().insert(recurringEntry) }

        val recurringBookEntry = BookEntry.create(
            title = TITLE,
            date = DATE,
            value = VALUE,
            isPaid = IS_PAID,
            notes = NOTES,
            entryType = ENTRY_TYPE,
            categoryId = CATEGORY_ID,
            contacts = CONTACTS,
            recurringEntryId = recurringEntryId
        )

        runBlocking {
            db.bookEntryDao().insert(recurringBookEntry) // BreakPoint #1
        }
    }

    @Test
    fun testInsertRecurrencesAndSchedule() { 
        var recurringEntry = runBlocking { db.recurringEntryDao().get(recurringEntryId) } // BreakPoint #2

        assertThat(recurringEntry, notNullValue())

        runBlocking { RecurrenceManager.insertRecurrencesAndSchedule(ApplicationProvider.getApplicationContext(), db, recurringEntry!!) }

        val bookEntries = db.bookEntryDao().getBookEntries().liveDataValue()
    }
}

This is the function for inserting:

@Transaction
suspend fun insert(bookEntry: BookEntry): Long {
    val id = insert(bookEntry.entity)
    bookEntry.embeddedContacts?.apply {
        forEach {
            it.id = 0
            it.bookEntryId = id
        }
    }?.let {
        insert(it)
    }

    return id
}

So if I'm running the test like it is (see BreakPoint #1), BreakPoint #2 won't even be called, so the test ends somewhere before, without a result.

If I'm replacing the code at BreakPoint #1 with exact the same code, the insert function has, the test runs correctly.

Does anyone have an idea what's the issue here?

That's because you are assering without the runblocking has finished — coroutineDispatcher, May 30 '19 at 14:31
@Stavro Xhardha I thought runblocking waits until the body has finished? Any way to solve this? — the_dani, Jun 02 '19 at 20:08
well I don't really know the way you are using. But check my post on the last section I am testing a room insert and select. check [this](https://link.medium.com/oTqhCh3wcX) — coroutineDispatcher, Jun 02 '19 at 20:53
Answers on this related question by me suggest that this is not possible, at the moment :( https://stackoverflow.com/questions/57027850/testing-android-room-with-livedata-coroutines-and-transactions — Martin Melka, Aug 19 '19 at 09:41

score 27 · Answer 1 · answered Sep 12 '19 at 05:55

27

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()
}

answered Sep 12 '19 at 05:55

sumit matta

744
7
8

3

Great! For users of kotlinx.coroutines 1.6.0: also works with **runTest** – Mateusz Piotrowski Feb 02 '22 at 17:25

score 6 · Answer 2 · edited Jul 17 '20 at 10:09

6

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!

edited Jul 17 '20 at 10:09

RealityExpander

133
1
8

answered Jun 07 '19 at 23:34

Hakem Zaied

14,061
1
23
25

1

Well, the test runs now, but I need the `InstantTaskExecutorRule` for the `liveDataValue()` method, because after removing this line, an error is thrown: `java.lang.IllegalStateException: Cannot invoke observeForever on a background thread`. – the_dani Jun 09 '19 at 18:46
1

How did you get it working with `InstantTaskExecutorRule `? – Hakem Zaied Jun 09 '19 at 18:52
The test runs, after removing InstantTaskExecutorRule, but now I've an error with observeForever. – the_dani Jun 09 '19 at 20:25
My `.liveDataValue()` extension function is a copy of this one: https://github.com/googlesamples/android-architecture-components/blob/master/GithubBrowserSample/app/src/test-common/java/com/android/example/github/util/LiveDataTestUtil.kt – the_dani Jun 09 '19 at 21:08
1

Is there a possibility to test LiveData + Coroutines? – the_dani Jun 12 '19 at 19:17
I not sure to be honest. But I wasn't able to get it working – Hakem Zaied Jun 15 '19 at 22:04

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

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