除非打印,否则Scala :: lazy值为null？

trait A {
  val eventStream: EventStream
  val credentialsStorage = // something here
  val userStorage = // something here
  val crypto = // something here
  ...    
  lazy val authSvc = new CoreAuthentication(credentialsStorage,new AuthenticationProviderResolver,userStorage,eventStream,crypto)
}

class T extends A with TraitProvidingEventStream with FlatSpec with [lot of another traits here] {

  val eventStream = systemFromTraitProvidingEventStream.eventStream

  "This" should "work" in {
    println(authSvc) // this is "magic"
    val user = authSvc.doSomethingWithUser(...);
  }
}

如果我删除标记为//这是“魔术”的行,那么我将在下一行获得NullPointerException,因此authSvc为null.

那可能有什么问题？

我无法为此创建干净的小测试用例,通常这种方法效果很好