[Koin 1.0] Testing improvements with declareMock() & declare()

[arnaudgiuliani]

Hello,

koin-test will no rely on mockito to provide out of the box mocking.

You can now directly declare a mock from a KoinTest file with declareMock():

val mod = module {
                single { ComponentA() }
                single { ComponentB(get()) }
            }
@Test
    fun `successful override factory with a mock`() {
        startKoin(listOf(mod))
        
       // will override ComponentA with mock definition
        declareMock<ComponentA>()
    }

You can also declare some components with declare { }, if you need more complex expression:

@Test
    fun `successful override factory with a mock`() {
        startKoin(listOf(mod))
        
        // will override ComponentA with mock definition
        declare { factory { DumbComponentA() } }
    }

No need to declare a special module, if you have only local expressions/mocks.

Available in koin-test version 1.0.0-beta-1.

[patrice-conil]

Nice,
I 'll play with it.
Patrice

[patrice-conil]

Hi @arnaudgiuliani
I played a bit with it ... and discovered that I haven't understood very well the usage of bind.

Writing two tests (first fails, second succeeds)

   @Test
    fun `successful override with an interface mock`() {
        startKoin(listOf(
                module {
                    single { ComponentA() } bind InterfaceA::class
                    single { ComponentB(get()) }
                }
        ))

        createMock<InterfaceA>()

        val mockA = get<InterfaceA>()
        Assert.assertEquals(mockA, get<ComponentB>().componentA)

        assertDefinitions(2)
        assertRemainingInstances(2)
    }

    @Test
    fun `successful override with an interface mock 2`() {
        startKoin(listOf(
                module {
                    single { ComponentA() as InterfaceA }
                    single { ComponentB(get()) }
                }
        ))

        createMock<InterfaceA>()

        val mockA = get<InterfaceA>()
        Assert.assertEquals(mockA, get<ComponentB>().componentA)

        assertDefinitions(2)
        assertRemainingInstances(2)
    }

I found a way to succeed but is-it an undocumented feature(AKA bug) or the behavior you expect ?
Patrice

[arnaudgiuliani]

Thanks for your feedback!

Yeah, it's because val mockA = get<InterfaceA>() will just declare a single { mock<InterfaceA>() } and not single { ... } bind InterfaceA::class

I've added a fix. To override your definition single { ComponentA() } bind InterfaceA::class, you will have to write createMock<ComponentA>(binds = listOf(InterfaceA::class))
The fix add the possibility to put some classes in binds section of the definition.

[arnaudgiuliani]

since 1.0.0-alpha-29

[patrice-conil]

Nice and clear,
I had to revert to kotlin 1.2.41 in a local version of koin to deal with android binding bug https://issuetracker.google.com/issues/110198434
I continue my investigations.
Patrice

[patrice-conil]

Thanks Arnaud,
Now we have an nice way to do what we want
I wrote a sample project using createMock that you can find here /~https://github.com/patrice-conil/testKoinMockBean
Patrice

[arnaudgiuliani]

Cool :)
I' had to rename it declareMock to not conflict with the createMock() from mockito.

[patrice-conil]

Sample updated with declareMock.
Now , I'm waiting for the release ;)

[Liako]

Hello @arnaudgiuliani i am facing aproblem i have updated to the latest V3 and my test are not running because of the declare method. I am attaching you the code currently using

fun createUserScopeFor(username: String): Scope {
koin.getScopeOrNull(Scopes.USER_SESSION)?.close()
return koin.createScope(Scopes.USER_SESSION, named(Scopes.USER_SESSION))
.apply {
declare(UserIdentifier(username))
get().create(this)
}
.also(::updateTrackingState)
}

and then trying to run a RxChain for a purpose when it reaches the create userScope it throughs a null pointer which comes when the code riches the declare function.

My test is like this
@test
fun login completes successfully when all requests succeed() {
val builder = ArrangeBuilder().withAllRequestsSucceeding()

        val subscription = useCase.credentialsLogin(USERNAME, PASSWORD, true).test()
        testScheduler.triggerActions()

        subscription.assertValue { it.isEnrolled() }
        verify(builder.appUpdateService).appUpdateCheck(any())
        verify(builder.tokenService).login(any(), any())
    }

And i am mocking the koin thingies like follow

whenever(koin.createScope(Scopes.USER_SESSION, named(Scopes.USER_SESSION))).thenReturn(
userScope
)

where user scope is mock() and
whenever(userScope.get()).thenReturn(mock())
When i run the test i am getting something like

If i memove the declare(UserIdentifier(username)) then the test is running properly. Could you please provide me with some hints how this could be done