synchronizing on database events

my opinions.kt

@Test fun `should receive updated data when querying all challenges`() = runBlocking<Unit> {

    //setup
    val initChallenges = list(Challenge(...),Challenge(...))
    val newSurveyChallenge = SurveyChallenge(...)
    val expectedChallenges = initChallenges + newSurveyChallenge

    //act
    initChallenges.forEach(challengeDao::addOrUpdate)
    challengeDao.addOrUpdate(newSurveyChallenge)
    val actualChallenges = withTimeoutOrNull(300 * 10) {
   
        repository.availableChallenges(coroutineContext).take(expectedChallenges.size).toList()
        
        //note: if you're not certain you've got cancellation on the `availableChallenges` implemented correctly, 
        // you might wrap the above line in async(IO) { ...availableChallenges() }.await().take(expected...
        // that will give the `withTimeoutOrNull` something to 'bite' into, but it could leave you with a lingering open connection. 
        // Some @Before and @After/Teardown logic is probably best here.
    }
    
    //assert
    assertThat(actualChallengesLists).isEqualTo(expectedChallenges)
}

origina.kt

 @Test
    fun `should receive updated data when querying all challenges`() {
        val initChallenges = mutableListOf(Challenge(...),Challenge(...))

        val newSurveyChallenge = SurveyChallenge(...)

        val expectedChallenges = listOf(
            initChallenges,
            initChallenges += newSurveyChallenge
        )

        initChallenges.forEach(challengeDao::addOrUpdate)

        runBlocking {
            val channel = repository.availableChallenges(coroutineContext)

            val actualChallengesLists = async(IO) {
                channel.fold(mutableListOf<List<Challenge>>()) { list, challenges -> list.apply { add(challenges) } }
            }

            delay(300)
            challengeDao.addOrUpdate(newSurveyChallenge)
            delay(300)
            channel.cancel()

            assertThat(actualChallengesLists.await()).containsExactlyElementsIn(expectedChallenges).inOrder()
        }