fix: fix the bug when imagetag is none

Author: j5ik2o

docker-controller-scala-core/src/main/scala/com/github/j5ik2o/dockerController/DockerController.scala

@@ -74,9 +74,11 @@ private[dockerController] class DockerControllerImpl(
     outputFrameInterval: FiniteDuration = 500.millis
 )(
     val imageName: String,
-    val tag: Option[String] = None
+    _tag: Option[String] = None
 ) extends DockerController {
 
+  val tag: Option[String] = _tag.orElse(Some("latest"))
+
   protected val logger: Logger = LoggerFactory.getLogger(getClass)
 
   private var _containerId: Option[String] = _
@@ -188,7 +190,7 @@ private[dockerController] class DockerControllerImpl(
 
   override def pullImageIfNotExists(f: PullImageCmd => PullImageCmd): Unit = {
     logger.debug("pullImageIfNotExists --- start")
-    if (!existsImage(p => p.getRepoTags.contains(repoTag))) {
+    if (!existsImage(p => Option(p.getRepoTags).exists(_.contains(repoTag)))) {
       pullImage(f)
     }
     logger.debug("pullImageIfNotExists --- finish")

docker-controller-scala-dynamodb-local/src/test/scala/com/github/j5ik2o/dockerController/dynamodbLocal/DynamoDBLocalControllerSpec.scala

@@ -17,7 +17,7 @@ class DynamoDBLocalControllerSpec extends AnyFreeSpec with DockerControllerSpecS
   logger.debug(s"testTimeFactor = $testTimeFactor")
 
   val hostPort: Int                       = temporaryServerPort()
-  val controller: DynamoDBLocalController = new DynamoDBLocalController(dockerClient)(hostPort)
+  val controller: DynamoDBLocalController = new DynamoDBLocalController(dockerClient, imageTag = None)(hostPort)
 
   // val waitPredicate: WaitPredicate = WaitPredicates.forListeningHostTcpPort(dockerHost, hostPort)
   val waitPredicate: WaitPredicate = WaitPredicates.forLogMessageByRegex(