如何使用 Mockito 模拟 Scala 对象中的函数？

Question

我是 Scala 的新手。我尝试使用 Mockito 模拟一个简单的 Scala 函数，但出现以下错误。我已经上网查了，但没能找出错误。

object TempScalaService {
  def login(userName: String, password: String): Boolean = {
    if (userName.equals("root") && password.equals("admin123")) {
      return true
    }
    else return false
  }
}

我的测试class如下

class TempScalaServiceTest extends FunSuite with MockitoSugar{

  test ("test login "){
    val service = mock[TempScalaService.type]
    when(service.login("user", "testuser")).thenReturn(true)
    //some implementation
  }
}

但是我收到以下错误：

Cannot mock/spy class     com.pearson.tellurium.analytics.aggregation.TempScalaService$
Mockito cannot mock/spy following:
- final classes
- anonymous classes
- primitive types
org.mockito.exceptions.base.MockitoException: 
Cannot mock/spy class    com.pearson.tellurium.analytics.aggregation.TempScalaService$
Mockito cannot mock/spy following:
- final classes
- anonymous classes
- primitive types
   at  org.scalatest.mock.MockitoSugar$class.mock(MockitoSugar.scala:74)
    at    com.pearson.tellurium.analytics.aggregation.TempScalaServiceTest.mock(Temp    ScalaServiceTest.scala:7)
at     com.pearson.tellurium.analytics.aggregation.TempScalaServiceTest$$anonfun$    1.apply$mcV$sp(TempScalaServiceTest.scala:10)
    at    com.pearson.tellurium.analytics.aggregation.TempScalaServiceTest$$anonfun$    1.apply(TempScalaServiceTest.scala:9)
    at     com.pearson.tellurium.analytics.aggregation.TempScalaServiceTest$$anonfun$    1.apply(TempScalaServiceTest.scala:9)
    at    org.scalatest.Transformer$$anonfun$apply.apply$mcV$sp(Transformer.scala:    22)
    at org.scalatest.OutcomeOf$class.outcomeOf(OutcomeOf.scala:85)

Answer 1

您不能模拟对象，请尝试将您的代码移动到 class:

class TempScalaService() {
  def login(userName: String, password: String): Boolean = {
    if (userName.equals("root") && password.equals("admin123")) {
      return true
    }
    else return false
  }
}

并创建服务：

object TempScalaService {
   private val service = TempScalaService()

   def apply() = service
}

如果使用依赖项注入框架会更好，但现在可以使用。

现在，为了测试，使用：

val service = mock[TempScalaService]
when(service.login("user", "testuser")).thenReturn(true)

Answer 2

您可以在对象扩展的特征中定义方法。然后简单地模拟特征：

trait Login {
  def login(userName: String, password: String): Boolean
}

object TempScalaService extends Login {
   def login(userName: String, password: String): Boolean = {
     if (userName.equals("root") && password.equals("admin123")) {
   return true
   }
    else return false
  }
}

//in your test
val service = mock[Login]

Answer 3

您可以创建一个 Scala 伴随对象：

为您编写测试用例class。
让那个对象做外部世界的交互。

如何使用 Mockito 模拟 Scala 对象中的函数？

How to mock a function within Scala object using Mockito?

scala

mockito

scalatest