Rxjava schedulers. Immediate() behavior during unit testing

I'm trying to write tests for Dao objects that use a reactive interface. I have a table containing recipes. I want to test it. When I insert data into the table, subscribers will receive a list containing recipes

I am using the testsubscriber class and executing assertions on it. My simple test is as follows:

@Test
fun testSubscriber() {
    insertItem()
    val testSubscriber = TestSubscriber.create<List<Recipe>>()

    recipeDao
            .getRecipes()
            .subscribeOn(Schedulers.immediate())
            .subscribe(testSubscriber)

    testSubscriber.assertNoErrors()
    testSubscriber.assertNoTerminalEvent()
    testSubscriber.assertNotCompleted()
    testSubscriber.assertValueCount(1)
    assertEquals(1, testSubscriber.onNextEvents[0].size)
}

The problem is that the assertion of testsubscriber.assertvaluecount (1) failed because no items were issued. However, when I insert this line above, testsubscriber.awaitterminalevent (500, timeunit. Milliseconds), the test was successful. My observable will not issue terminal events, so it will execute timeout, but while waiting, I called onnext using the recipe list

My getrecipes method:

fun getRecipes(): Observable<List<Recipe>> {
    return query(SELECT("*")
            .FROM(Recipe.TABLE_NAME)
            .ORDER_BY(Recipe.COL_NAME))
            .run()
            .mapToList(RecipeMapper.MAPPER)
}

How is that possible? I think that when I use schedulers. Immediate(), the operation will be executed on the same thread and my testsubscriber will receive events. If not, how should I write this test to make it successful? I want to test whether onnext is called, and I don't want to insert an artificial sleep command between the two

resolvent:

The problem is that I am using the library sqlbrite with the additional framework sqlbrite Dao. Sqlbrite is observing queries on a specific scheduler and will use schedulers. Io() when no queries are provided to the daomanager of sqlbrite Dao. The solution is to provide a scheduler to daomanager. Builder, or apply rxjavaplugins and return schedulers. Immediate() as all schedulers