我正在尝试为 Akka Actor 编写单元测试。
下面是单元测试代码
import org.scalatest._
import akka.testkit.{TestKit, ImplicitSender, TestActors}
import akka.actor.ActorSystem
class PipFilterTest
extends TestKit(ActorSystem("testSystem"))
with BeforeAndAfterAll
with ImplicitSender
with WordSpecLike {
override def afterAll(): Unit = {
TestKit.shutdownActorSystem(system)
}
"PipeFilter Actor" must {
"send messages if it passes the filter criteria" in {
//test code
}
}
}
当我尝试运行测试代码时,出现以下错误 -
sbt:chapter8_structuralPatterns> test
[info] Compiling 1 Scala source to /rajkumar_natarajans_directory/projectName/target/scala-2.12/test-classes ...
[error] /rajkumar_natarajans_directory/projectName/src/test/scala/PipeFilterTest.scala:13:7: overriding method run in trait BeforeAndAfterAll of type (testName: Option[String], args: org.scalatest.Args)org.scalatest.Status;
[error] method run in trait WordSpecLike of type (testName: Option[String], args: org.scalatest.Args)org.scalatest.Status needs `abstract override' modifiers
[error] class PipFilterTest extends TestKit(ActorSystem("testSystem")) with StopSystemAfterAll with ImplicitSender with WordSpecLike {
[error] ^
[error] one error found
[error] (Test / compileIncremental) Compilation failed
当我删除with BeforeAndAfterAll
并beforeAll
和afterAll
方法时,测试运行良好。但是我需要这些来设置测试参与者。知道为什么我会收到这些错误。
版本信息:
标量测试 3.0.5
阿卡 2.5.11
斯卡拉 2.12.4
这里编译并运行 scalac 2.12.4、akka 2.5.11、scalaTest 3.0.5:
import org.scalatest._
import akka.testkit.{TestKit, ImplicitSender, TestActors}
import akka.actor.ActorSystem
class PipFilterTest
extends TestKit(ActorSystem("testSystem"))
with WordSpecLike
with ImplicitSender
with BeforeAndAfterAll {
override def afterAll(): Unit = {
TestKit.shutdownActorSystem(system)
}
"PipeFilter Actor" must {
"send messages if it passes the filter criteria" in {
//test code
}
}
}
原因是:
- WordSpecLike 具有
run
的具体实现 - 只有在基类或前面的特征之一已经实现
run
如果你交换WordSpecLike
和BeforeAndAfterAll
,那么编译器认为你想混合WordSpecLike
,但BeforeAndAfterAll
然后没有什么可依赖的,因为之前没有实现run
的特质,因此整个编译失败。
这实际上非常直观:BeforeAndAfterAll
的run
应该看起来像这样:
abstract override def run(): CrazyScalatestResultType = {
beforeAll()
super.run()
afterAll()
}
如果没有实现run
的super
,那么BeforeAndAfterAll
也无法正常运行。
要点:混合顺序很重要。
可能相关的链接:Scala的可堆叠特征模式