Proper instrumentation test with Koin

Question

Can't get this thing to work correctly.

1. I have custom test application registered under test runner:

class HelloInstrumentationTestRunner : AndroidJUnitRunner() {
    override fun newApplication(
        cl: ClassLoader?, className: String?, context: Context?
    ): Application {
        return Instrumentation.newApplication(HelloTestApp::class.java, context)
    }
}

2. My application instance starts koin like usual:

        startKoin {
            androidLogger()
            androidContext(applicationContext)
            fragmentFactory()
            modules(appModule + viewModelsModule)
        }

3. Problem 1: In my instrumentation tests, I cannot do stopKoin() (says No Koin Context configured. Please use startKoin or koinApplication DSL)
4. Problem 2: When I try to workaround the situation with unloadKoinModules/loadKoinModules in @After, my declareMockin subsequent test methods are no longer working.

All these problems are basically because application instance survives between tests, thus graph configured inside android application instance also survives between tests. I need that not to happen or at least have ability to modify graph between tests.

Answer 1

Solved.

1. I had to setup override module:

    val overrideModule = module(override = true) {
        single<Repository1> {
            mock(Repository1::class.java)
        }
        single { Repository2(get(), get()) }
        single<Repository3> {
            mock(Repository3::class.java)
        }
        ...
    }

2. In my @BeforeTest, I now do loadKoinModules(overrideModule)
3. In my @AfterTest, I do unloadKoinModules(overrideModule)
4. Inside my tests, I can now do:

        given(get<Repository1>().magicCall()).willReturn(
            MagicData(
                "1111",
                Calendar.getInstance().timeInMillis
            )
        )

No need to deal with stopKoin and stuff like that, super easy!