Hello guys, I need some help regarding the usage of the application.conf file. I have a service which reads his configuration from application.conf:

class MqttHandler : SensorExchangeUseCase {
    /**
     *  Factory to read the application.conf file
     *  <https://stackoverflow.com/questions/53891189/how-do-i-use-custom-configuration-in-ktor>
     */
    private val config: MqttConfig = with(ConfigFactory.load()) {
        MqttConfig(
            this.getString("mqtt.topic"),
            getString("mqtt.brokerUrl"),
            getInt("mqtt.port"),
            getString("mqtt.clientId")
        )
    }

To test that, I created the following test:

class MqttHandlerTest : FunSpec({
    withTestApplication {
        (environment.config as MapApplicationConfig).apply {
            put("mqtt.topic", "karlheinz")
            put("mqtt.brokerUrl", container.host)
            put("mqtt.port", port.toString())
            put("mqtt.clientId", "Karl")
        }
        main()
    }


    test("should read correct Config from HOCON File") {
        with(ConfigFactory.load()) {
            getString("mqtt.topic") shouldBe "karlheinz"
            getString("mqtt.brokerUrl") shouldBe container.host
            getInt("mqtt.port") shouldBe port
            getString("mqtt.clientId") shouldBe "Karl"
        }
    }

However, my test fails since it loads the values which are in my local file and not the values that I put there with

withTestApplication

. My Service is not an application module. How could I test the behaviour? It feels like I'm missing something. Thanks in advance!

ktor's config stuff is overcomplicated and unnecessary, IMO. I'd skip it and do config with tools of your choosing in a way that fits more naturally with your project's structure.