JUnit4 rule and JUnit5 extension with annotation for injecting DAOs into tests

[sczerwinski]

JUnit4 examples:

class SomeTestWithDatabase {

    @Rule
    @JvmField
    val roomDatabaseRule = RoomDatabaseRule<MyDatabase>()

    @RoomDao
    lateinit var fooDao: FooDao

    // ...
}

JUnit5 examples:

@ExtendWith(RoomDatabaseExtension::class)
class SomeTestWithDatabase {

    @RoomDao
    lateinit var fooDao: FooDao

    // ...
}

Questions:

• How to provide database type to the extension? (easy with rules)
• How to provide advanced database configuration (callbacks, migrations, allow main thread queries, in-memory, etc.) without complicating tests too much?
• Does this really improve the readability of the tests?