Hi guys, I have a Ktor `HttpClient` set like so: `...

# ktor

[Archie]

Hi guys, I have a Ktor HttpClient set like so:

HttpClient(engine) {
    defaultRequest {
        header("A Header", headerValue)
    }
}

I wanted to add a test to that ensures that everytime I make a request to the HttpClient it would add the stated header. Is there a way to do this test?

[Hamza]

have u tried reading the tests written for the client and see how they test headers?

[andev]

assertNotNull(call.request.header("A Header"))

[andev]

nevermind, didn't see u asked about client

[andev]

But honestly, you should test only your code. By using the Client, u already trust its developers that they did the good job.

[marstran]

@andev He doesn't really test the HttpClient though. I think he wants to test that his own code adds that header.

[russhwolf]

Pass MockEngine to your client. You can read the headers from the request when you construct your mock response

[andev]

Yep, just as Russell said

@Test
fun test() {
    val client = HttpClient(MockEngine) {
        expectSuccess = false
        engine {
            addHandler { request ->
                assertNotNull(request.headers.get("A Header"))
                respondOk("REPLACE WITH YOUR MOCK RESPONSE")
            }
        }
    }
}

[Archie]

@andev YES! thats what I need thank you very much!!

[Matteo Mirk]

Still, I’m convinced that if you setup the client like that, you’re already trusting Ktor to do its job, which is already covered by their test suite.

I my modest opinion I think testing for the presence of your header in this setting is redundant like testing that an Apache HttpClient initialized such and such stays the same for every request, or that every @Autowired usage works in your spring application.

[Archie]

I honestly disagree.. The test I want to write isn't testing Ktor itself but instead Testing the setup I made. So if someone in the project messed up and accidentally delete some setup, (like the header above) the test would easily tell me what to fix or what was missing. Its not about whether Ktor would add the header that I specified. Its for reflecting the setup of the app. Not Ktor.

[Matteo Mirk]

Cool… just maybe a thumb down is a little too harsh for having expressed an opinion?
Anyway, regarding this matter, probably I didn’t express myself good enough. The fact that you want to test the header setup for your app, is still indirectly testing Ktor. Quoting your initial message:

I wanted to add a test to that ensures that everytime I make a request to the HttpClient it would add the stated header.

if this is not exactly testing that Ktor works as designed, I don’t know what else it is. 😄
If someone in the project accidentally deletes the setup then you have a bigger problem than a functional requirement…
Maybe your test focus should be shifted, not checking the http client setup but rather the receiving point should test for its required headers. Anyway, I can see your initial point, just wanted to offer a different test design perspective, sorry if I wasn’t clear before.