Testing Android Room with LiveData, Coroutines and Transactions

Question

I want to test my database layer and I have caught myself in a catch-22 type of a situation.

The test case consists of two things:

• Save so

Answer 1

There is now a solution to this issue, explained in this answer.

The fix is adding a single line to the Room in-memory database builder:

db = Room
    .inMemoryDatabaseBuilder(context, AppDatabase::class.java)
    .setTransactionExecutor(Executors.newSingleThreadExecutor()) // <-- this makes all the difference
    .build()

With the single thread executor the tests are working as expected.