write a unit test for this kotlin class.

open class SqsSender( private val sqsClient: SqsClient, private val queueName: String ) : MessageSender { @Volatile private lateinit var queueUrl: String @PostConstruct fun init() { // Create topic val (_: String, dlqArn: String) = MessagingUtils.createDeadLetterQueue(sqsClient, queueName) // Create main queue val (url: String, queueArn: String) = MessagingUtils.createQueue(sqsClient, queueName, dlqArn) queueUrl = url } override fun send(message: String) { sqsClient.sendMessage( SendMessageRequest .builder() .queueUrl(queueUrl) .messageBody(message).build() ) } }