可以将Akka中的testkit版本升级到2.6以上，这个版本支持Akka的typed API。同时，需要将依赖项更新为akka-actor-typed和akka-actor-testkit-typed。接下来，按照下面的方式进行测试即可：

import akka.actor.testkit.typed.scaladsl.{ActorTestKit, LogCapturing}
import org.scalatest.{BeforeAndAfterAll, Matchers, WordSpecLike}

class MyActorSpec extends WordSpecLike with Matchers with BeforeAndAfterAll with LogCapturing {
  val testKit = ActorTestKit()

  override def afterAll(): Unit = testKit.shutdownTestKit()

  "A MyActor" should {
    "reply with a greeting" in {
      val myActor = testKit.spawn(MyActor())
      val replyTo = testKit.createTestProbe[Greeting]()
      myActor ! Greet("Akka", replyTo.ref)
      replyTo.expectMessage(Greeting("Hello, Akka!"))
    }
  }
}

这样的话，就可以在使用Akka的typed API的时候，用Akka testkit进行测试了。