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I am trying to test below method and assert that `...
# coroutines
v
I am trying to test below method and assert that 
remoteCloudDataStore.getFoodItems()
and 
localDataStore.addFoodItems(it)
methods are called 
exactly once
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fun getFoodItems(forceNetworkFetch: Boolean) = remoteCloudDataStore.getFoodItems().flatMapConcat {
        localDataStore.addFoodItems(it).flatMapConcat {
            flow { emit(FoodResult.Success(it)) }
        }
    }.flowOn(<http://dispatcher.io|dispatcher.io>)
Below is my test case
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repository.getFoodItems(true).collect {
            verify(exactly = 1) { remoteCloudDataStore.getFoodItems() }
            verify(exactly = 5) { localDataStore.addFoodItems(any()) }
        }
Surprisingly this test case pass, even if addFoodItems() method is not being called 5 times, can someone point me in correct direction what I am doing wrong here? I am passing 
TestCoroutineDispatcher
during testing.
l
for a test I would do
repository.getFoodItems(true).toList() verify(exactly = 1) { remoteCloudDataStore.getFoodItems() } verify(exactly = 5) { localDataStore.addFoodItems(any()) }
j
Those are both terminal in my understanding (collect/toList) so why would collect not work? Maybe coVerify is needed here and not just normal verify when using mockk
v
even after coVerify test passes, my expectation is this test should fail, because 
localDataStore.addFoodItems
is not being called 5 times in method body.
If I do 
toList()
I receive:
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io.mockk.MockKException: Missing calls inside verify { ... } block.
j
Sorry @Luis Munoz code looks correct to me so I guess I can't help any more. I would be interested in what you find though if you care to share in the future
l
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remoteCloudDataStore.getFoodItems() returns a flow
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verify(exactly = 1) { remoteCloudDataStore.getFoodItems().toList() }
probably wrong you want to see how many items are in the list?
v
I am more curious about how to verify method interaction
how many items
test case is planned for sure 🙂
l
if remoteCloudDataStore.getFoodItems() returns a flow you gotta terminate it
that is why I suggest you use toList to terminate everything
before doing assertions
v
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repository.getFoodItems(true).collect {
coVerify(exactly = 1) { remoteCloudDataStore.getFoodItems().toList() }
coVerify(exactly = 5) { localDataStore.getFoodItems().toList() }
}
Didn’t help
Test case still passes
l
assertThat(remoteCloudDataStore.getFoodItems().toList().size).isEqualTo(1)
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assert localDataStore.getFoodItems().toList().size  is equal to 5
j
he wants to check the number of calls to his mock dependency. I believe you had it right the first time.
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val items = repository.getFoodItems(true).toList()
verify(exactly = 1) { remoteCloudDataStore.getFoodItems() }
l
there isn't enough information
are you using runBlocking?
j
or runBlockingTest
v
I tried with both runBlocking & runBlockingTest
On debugging i am seeing that it doesn’t come other collect method.
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repository.getFoodItems(true).collect {
            verify(exactly = 11) { remoteCloudDataStore.getFoodItems() }
        }
l
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@Test
    fun `force fetching foodItems makes network and db call`() =   {
      val latch = CountDownLatch(1)
      dispatcher.runBlockingTest {

        coEvery { restApi.getFoodItems() } returns MockData.foodItems
        every { localDataStore.addFoodItems(any()) } returns flow { MockData.foodItem }

        repository.getFoodItems(true).collect {
        
            verify(exactly = 11) { remoteCloudDataStore.getFoodItems() }
            latch.countDown()
            
        }
        
        
    }
     
      latch.await(3, TimeUnit.Seconds)
    
    }
never used TestCoroutineDispatcher so I'm not sure. Just make sure 1) that it actually calls the assertion (put a print statement before and after it). 2) that if an error gets thrown it is propagated not swallowed (do a throw RuntimeException and see that test fails and shows exception 3) that everything isn't async and just passes right through the test even when work is still being done in a background thread, you can use CountDownLatch to mark these points
doing assertion inside of collect seem wrong to me
if you only emit once why is it a flow and not a just a suspend, and if you emit more than once then how can you assert multiple times different items
j
@Vipul just to be clear, you verified in a runBlocking statement AFTER the call to collect?
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val items = repository.getFoodItems(true).toList()
verify(exactly = 1) { remoteCloudDataStore.getFoodItems() }
IE verify after the flow has terminated
v
yes I am verifying under collect
j
That does not look like what you Luis is saying. you are verifying in the collect lambda
Did you try this:
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coEvery { restApi.getFoodItems() } returns MockData.foodItems
every { localDataStore.addFoodItems(any()) } returns flow { MockData.foodItem }

repository.getFoodItems(true).toList()
verify(exactly = 11) { remoteCloudDataStore.getFoodItems() }
v
yup, didnt worked
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repository.getFoodItems(true).toList()
verify(exactly = 11) { remoteCloudDataStore.getFoodItems() }
l
also you are doing
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remoteCloudDataStore.getFoodItems().flatMapConcat
but getFoodItems is a mock object?
so it doesn't have flatMapConcat
v
nope, I am having mock on 
restApi.getFoodItems()
level
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remoteCloudDataStore = CloudCloudDataStoreImpl(restApi)
so following gets called
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restApi.getFoodItems()
l
project looks interesting i'll clone it and run it in a few minutes
🙏 1
first notice that
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@Test
    fun `force fetching foodItems makes network and db call`() =

            dispatcher.runBlockingTest {

        coEvery { restApi.getFoodItems() } returns MockData.foodItems
        every { localDataStore.addFoodItems(any()) } returns flow { MockData.foodItem }

        repository.getFoodItems(true).collect {

            throw RuntimeException("test should fail")
            verify(exactly = 11) { remoteCloudDataStore.getFoodItems() }
        }
    }
does not fail
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@Test
    fun `force fetching foodItems makes network and db call`() =

            dispatcher.runBlockingTest {

        coEvery { restApi.getFoodItems() } returns MockData.foodItems
        every { localDataStore.addFoodItems(any()) } returns flow { MockData.foodItem }

        repository.getFoodItems(true).toList()

          //  throw RuntimeException("test should fail")
            coVerify(exactly = 11) { remoteCloudDataStore.getFoodItems().toList() }

    }
is probably what you want
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override fun getFoodItems(forceNetworkFetch: Boolean): Flow<FoodResult<List<FoodItem>>>
that signature is making the code overly complicated in my opinion
do you need to stream out multiple lists as a flow or can you just return a list of the collected items
v
I got your point, I can refactor it to just return list
but I am curious about this failed test 😄
did it run for you?
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