@Serializable
data class TestDataClass(
	val a: String
)

MockEngine {
   respond(
      content = Json.encodeToString(TestDataClass("hello")),
      status = HttpStatusCode.OK,
      headers = headersOf(HttpHeaders.ContentType, ContentType.Application.Json.toString())
   )
}

val httpClient = HttpClient(engine) {
		install(ContentNegotiation) {
			Json
		}
	}

val response = <http://httpClient.post|httpClient.post>("<http://localhost:8080/myurl>")

val testResult = response.body<TestDataClass>()