Scala testcontainers Kafka wrapper

KafkaContainer.scala

import com.dimafeng.testcontainers.SingleContainer
import org.testcontainers.containers.{KafkaContainer => OTCKafkaContainer}
import org.testcontainers.containers.{GenericContainer => OTCGenericContainer}

class KafkaContainer(confluentPlatformVersion: Option[String] = None,
                     externalZookeeper: Option[String] = None) extends SingleContainer[OTCGenericContainer[_]] {

  type OTCContainer = OTCGenericContainer[T] forSome {type T <: OTCKafkaContainer}

  var kafkaContainer: OTCKafkaContainer = null

  if (confluentPlatformVersion.isEmpty) {
    kafkaContainer = new OTCKafkaContainer()
  } else {
    kafkaContainer = new OTCKafkaContainer(confluentPlatformVersion.get)
  }

  if (externalZookeeper.isEmpty) {
    kafkaContainer.withEmbeddedZookeeper()
  } else {
    kafkaContainer.withExternalZookeeper(externalZookeeper.get)
  }

  override val container: OTCKafkaContainer = kafkaContainer

}

object KafkaContainer {
  def apply(confluentPlatformVersion: String = null, externalZookeeper: String = null): KafkaContainer = new KafkaContainer(Option(confluentPlatformVersion), Option(externalZookeeper))
}