Hi all, Looking for some testing suggestion with ...

# coroutines

[kev1n11]

Hi all,

Looking for some testing suggestion with coroutines, in particular CoroutineScope.

We are POCing the following into our Spring Boot server
• as the server starts up, use SqsAsyncClient to read in messages,
• these are sent into a buffered Channel,
• also start a pool of worker coroutines to process these messages, the processing functions are all suspend fun
The above are encapsulated in a SQSConsumer which implements CoroutineScope, and we cant seem to figure out a clean way to test that.

The code looks something like

class SQSConsumer(
    val sqs: SqsAsyncClient,
    val props: SQSProperties
) : CoroutineScope {
    private val supervisorJob = SupervisorJob()
    override val coroutineContext: CoroutineContext
        get() = <http://Dispatchers.IO|Dispatchers.IO> + supervisorJob

    // called from another class using @PostConstruct
    fun start() = launch {
        val launchQueueReceiveChannel = launchReceiver(
            props.queueUrl,
            props.waitTimeSeconds,
            props.maxNumberOfMessages
        )
        repeat(props.workers) {
            launchWorker(launchQueueReceiveChannel, props.queueUrl, props.timeout)
        }
    }
}

What are the common patterns for overriding Dispatcher in tests?

If you have a better suggest to encapsulate the above (Spring Boot or not), we’d love to hear too.

[Thiyagu]

https://github.com/thiyagu06/reactive-sqs-consumer

[Dominaezzz]

override the dispatcher via DI.