I am trying to test below method and assert that `remoteClou

Question

I am trying to test below method and assert that `remoteCloudDataStore getFoodItems ` and `localDataStore addFoodItems it ` methods are called `exactly once` ```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 ```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

Luis Munoz · Answer

for a test I would do

Luis Munoz · Answer

repository getFoodItems true toList verify exactly = 1 remoteCloudDataStore getFoodItems verify exactly = 5 localDataStore addFoodItems any

Justin Tullgren · Answer

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

Vipul · Answer

even after coVerify test passes my expectation is this test should fail because `localDataStore addFoodItems` is not being called 5 times in method body

Vipul · Answer

If I do `toList ` I receive ```io mockk MockKException Missing calls inside verify block ```

Justin Tullgren · Answer

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

Luis Munoz · Answer

```remoteCloudDataStore getFoodItems returns a flow```

Luis Munoz · Answer

```verify exactly = 1 remoteCloudDataStore getFoodItems toList ```

Luis Munoz · Answer

probably wrong you want to see how many items are in the list

Vipul · Answer

I am more curious about how to verify method interaction

Vipul · Answer

`how many items` test case is planned for sure slightly smiling face

Luis Munoz · Answer

if remoteCloudDataStore getFoodItems returns a flow you gotta terminate it

Luis Munoz · Answer

that is why I suggest you use toList to terminate everything

Luis Munoz · Answer

before doing assertions

Vipul · Answer

```repository getFoodItems true collect coVerify exactly = 1 remoteCloudDataStore getFoodItems toList coVerify exactly = 5 localDataStore getFoodItems toList ```

Vipul · Answer

Didn t help

Vipul · Answer

Test case still passes

Luis Munoz · Answer

assertThat remoteCloudDataStore getFoodItems toList size isEqualTo 1

Luis Munoz · Answer

```assert localDataStore getFoodItems toList size is equal to 5```

Justin Tullgren · Answer

he wants to check the number of calls to his mock dependency I believe you had it right the first time ```val items = repository getFoodItems true toList verify exactly = 1 remoteCloudDataStore getFoodItems ```

Luis Munoz · Answer

there isn t enough information

Luis Munoz · Answer

are you using runBlocking

Justin Tullgren · Answer

or runBlockingTest

Vipul · Answer

< Luis Munoz> Here is the file

Vipul · Answer

I tried with both runBlocking amp runBlockingTest

Vipul · Answer

On debugging i am seeing that it doesn t come other collect method ```repository getFoodItems true collect verify exactly = 11 remoteCloudDataStore getFoodItems ```

Luis Munoz · Answer

``` 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 ```

Luis Munoz · Answer

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

Luis Munoz · Answer

doing assertion inside of collect seem wrong to me

Luis Munoz · Answer

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

Justin Tullgren · Answer

< Vipul> just to be clear you verified in a runBlocking statement AFTER the call to collect ```val items = repository getFoodItems true toList verify exactly = 1 remoteCloudDataStore getFoodItems ```

Justin Tullgren · Answer

IE verify after the flow has terminated

Vipul · Answer

< Justin Tullgren> Here is the test file

Vipul · Answer

yes I am verifying under collect

Justin Tullgren · Answer

That does not look like what you Luis is saying you are verifying in the collect lambda

Justin Tullgren · Answer

Did you try this ```coEvery restApi getFoodItems returns MockData foodItems every localDataStore addFoodItems any returns flow MockData foodItem repository getFoodItems true toList verify exactly = 11 remoteCloudDataStore getFoodItems ```

Vipul · Answer

yup didnt worked ```repository getFoodItems true toList verify exactly = 11 remoteCloudDataStore getFoodItems ```

Luis Munoz · Answer

also you are doing

Luis Munoz · Answer

```remoteCloudDataStore getFoodItems flatMapConcat ```

Luis Munoz · Answer

but getFoodItems is a mock object

Luis Munoz · Answer

so it doesn t have flatMapConcat

Vipul · Answer

nope I am having mock on `restApi getFoodItems ` level

Vipul · Answer

```remoteCloudDataStore = CloudCloudDataStoreImpl restApi ```

Vipul · Answer

so following gets called ```restApi getFoodItems ```

Luis Munoz · Answer

project looks interesting i ll clone it and run it in a few minutes

Luis Munoz · Answer

first notice that

Luis Munoz · Answer

``` 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 ```

Luis Munoz · Answer

does not fail

Luis Munoz · Answer

``` 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 ```

Luis Munoz · Answer

is probably what you want

Luis Munoz · Answer

```override fun getFoodItems forceNetworkFetch Boolean Flow lt FoodResult lt List lt FoodItem gt gt gt ```

Luis Munoz · Answer

that signature is making the code overly complicated in my opinion

Luis Munoz · Answer

do you need to stream out multiple lists as a flow or can you just return a list of the collected items

Vipul · Answer

I got your point I can refactor it to just return list

Vipul · Answer

but I am curious about this failed test smile

Vipul · Answer

did it run for you