scala - 如何模拟 Scala 单例对象？

Question

我正在尝试模拟一个 Scala 单例对象。特别是，我需要模拟在服务组件(被测类)中使用的对象 play.api.libs.ws.WS。 使用 Mockito 这是不可能的，测试执行失败如下:

[error]    MockitoException: : 
[error] Cannot mock/spy class play.api.libs.ws.WS$
[error] Mockito cannot mock/spy following:
[error]   - final classes
[error]   - anonymous classes
[error]   - primitive types  (GeolocationSpec.scala:18)

阅读 here ，似乎 Scalamock 允许这样做:

To mock a standalone singleton object, use org.scalamock.annotation.mockObject.

我的服务组件是这样的:

trait GeolocationService {
  def wsClient = WS
  def getPath(origin: Location, destination: Location): Future[Route]
}

class DefaultGeolocationService extends GeolocationService {

  val serviceProviderEndpoint = Play.current.configuration.getString("api.directions.endpoint")

  override def getPath(origin: Location, destination: Location): Future[Route] = {

    val params = Seq(
      "origin" -> s"${origin.lat},${origin.lon}",
      "destination" -> s"${destination.lat},${destination.lon}"
    );
    val resp = wsClient.url(serviceProviderEndpoint.get).withQueryString(params: _*).get()
    resp.map {
      // omitted code
    }
  }
}

我的 build.sbt 具有所有这些依赖项:

[...]
"org.scalatest" %% "scalatest" % "2.2.1",
"org.specs2" %% "specs2" % "2.3.13" % "test",
"org.scalamock" %% "scalamock-specs2-support" % "3.0.1" % "test",
"org.scalamock" %% "scalamock-scalatest-support" % "3.0.1" % "test",
"org.scalamock" %% "scalamock" % "3.0.1",
[...]

但我找不到这个:org.scalamock.annotation.mockObject

可能这也可以使用 EasyMock 和 PowerMock 来完成，但我找不到任何 Scala 示例代码。

有什么想法吗？

Answer 1

使用 ScalaMock 3 模拟单例对象不可能，但是 Paul Butcher 希望在 ScalaMock 4 中重新引入此功能(参见 http://paulbutcher.com/2014/04/15/scalamock-status-report/)