Ktor integration test with custom hostname

Using ktor-testing I need to create a test which uses a custom hostname. (The reason I need this is that we use subdomains to select the upstream service, but that's not really important).

Anyway, I came up with this:

class MyApplicationTest {

    @Test
    fun testCustomHost() = testApplication {

        environment {
            connector {
                port = 80
                host = "example.com"
            }
        }

        application {
            routing {
                host("example.com") {
                    get("/my-path") {
                        call.respond(HttpStatusCode.Accepted)
                    }
                }
            }
        }

        val response = client.get("/my-path") {
            url {
                this.port = 80
                this.host = "example.com"
                this.protocol = URLProtocol.HTTP
            }
        }

        assertEquals(HttpStatusCode.Accepted, response.status)
    }
}

This test gives 404 Not Found instead of 202 Accepted. But if I change from "example.com" to "localhost" it works.

To solve the problem, send the Host header with the value example.com:

val response = client.get("http://example.com/my-path") {
    header(HttpHeaders.Host, "example.com")
}