I'm trying to set up mock http responses for my te...

# apollo-kotlin

[Magnus Gudmandsen]

I'm trying to set up mock http responses for my tests in a very minimal test, using the mockServerTest block in a very minimal test:

mockServerTest {
    mockServer.enqueue(mockResponse)
    MyService(apolloClient).getData()
}

However, I just get a UncompletedCoroutinesError (test coroutine not completing). The getData() function is a suspend function that just calls apolloClient.query(MyQuery).execute() , and returns the result.

[Stylianos Gakis]

Is it just this test, or all tests using this?
How are you setting up your ApolloClient + MockServer?

[Magnus Gudmandsen]

This is my first test using this, so yes to both 😄

I'm using the ApolloClient + MockServer provided through the mockServerTest block

[Magnus Gudmandsen]

This is the code for that setup (in the Apollo code):

val mockServer = MockServer()

  val apolloClient = ApolloClient.Builder()
      .serverUrl(mockServer.url())
      .build()

[mbonnin]

Is this native/JS by any chance?

[Magnus Gudmandsen]

Android codebase, JUnit test case

[mbonnin]

Welp, that's unexepcted...

[Magnus Gudmandsen]

How come? 😅

[mbonnin]

Maybe incopatible coroutine versions? Wild guess at this point... Can you share the full stacktrace?

[Magnus Gudmandsen]

My original idea was to try to use the MockServer just to mock a response directly in the Service itself, so I could run the app with mocked response for a specific server, but I couldn't figure out how to get that working either (it didn't like the url of the MockServer). Separate issue though.

[Magnus Gudmandsen]

stacktrace.txt

stacktrace.txt

[Stylianos Gakis]

Are you also using kotlin’s runTest somewhere in there?

I see that at one place I am using it, I am doing this https://github.com/HedvigInsurance/android/blob/41758c154b9483826864a5f67f0f301caa[…]54/app/app/src/test/kotlin/com/hedvig/app/apollo/ApolloUtils.kt but I don’t remember if I needed that or not. Might be unrelated though, don’t want to steer you too far from your original issue.

[Stylianos Gakis]

Seeing a lot of runTestCoroutineLegacy in there, are you using some old coroutine dependency with the old runBlockingTest which is now deprecated?

[Magnus Gudmandsen]

Hmm, the mockServerTest block calls kotlin's runTest internally, yes

[Magnus Gudmandsen]

kotlinCoroutines = "1.7.3"

[mbonnin]

Same version Apollo uses internally

[Stylianos Gakis]

If you also do something like this https://github.com/HedvigInsurance/android/blob/41758c154b9483826864a5f67f0f301caa[…]54/app/app/src/test/kotlin/com/hedvig/app/apollo/ApolloUtils.kt
With sample usage https://github.com/HedvigInsurance/android/blob/41758c154b9483826864a5f67f0f301caa[…]rc/test/kotlin/com/hedvig/app/apollo/PaymentQueryParsingTest.kt do you see the same issue?

[Magnus Gudmandsen]

I copied your runApolloTest function, and it definitely seems to work better! Now I'm just getting Failed to parse GraphQL http network response, but that's on me 😅

I'll get back to you to verify once this works all the way through.

In the meanwhile: Thanks for the help! 🙏

[Magnus Gudmandsen]

I wonder if it's just the TestDispatcher being supplied in your case that makes the difference? 🤔

[mbonnin]

mockServer was mostly intended for internal uses, we should probably hide it or rework the API a bit

[mbonnin]

Sounds like a dispatcher thing indeed kotlinx.coroutines allow you to inject a test dipatcher IIRC?

[Magnus Gudmandsen]

I tried to reduce the code to just this, and it still works the same 🤷

fun runApolloTest(
    block: suspend CoroutineScope.(MockServer, ApolloClient) -> Unit,
) {
    return kotlinx.coroutines.test.runTest {
        val mockServer = MockServer()
        val apolloClient = ApolloClient.Builder()
            .serverUrl(mockServer.url())
            .build()
        block(mockServer, apolloClient)
        apolloClient.close()
        mockServer.stop()
    }
}

[Stylianos Gakis]

Oh, now that’s confusing 😵‍💫 I figured that’s what would’ve made it work, but I was wrong then. So this last snippet works perfectly fine in your case right?

[Magnus Gudmandsen]

I'm still struggling to understand what's wrong with my response body, but I'm getting that error, instead of the other one, yes 😬

[Stylianos Gakis]

Maybe time to get even more inspiration from what I’ve done? 😄
We have this https://github.com/HedvigInsurance/android/blob/41758c154b9483826864a5f67f0f301caa[…]54/app/app/src/test/kotlin/com/hedvig/app/apollo/ApolloUtils.kt with sample usage here https://github.com/HedvigInsurance/android/blob/4a89b94a1c26b41b11ac6ecf3995760527[…]est/kotlin/com/hedvig/app/apollo/EmbarkStoryQueryParsingTest.kt.
This makes it so that you can take a response object (Operation.Data) just as you would from the backend anyway, and turn it back into Json to feed it into your mock server.

You can even combine all this with the test data builders, like here https://github.com/HedvigInsurance/android/blob/4a89b94a1c26b41b11ac6ecf3995760527[…]est/kotlin/com/hedvig/app/apollo/EmbarkStoryQueryParsingTest.kt to make the entire experience very nice tbh.

[Magnus Gudmandsen]

Just for the sake of completeness, my graphql parse failed due to not having __typename in the body for fragments... fun times!

Now everything works, data is parsed, and the test passes!

Thanks a lot for the help 🙂