如何使用 Mockito 在 Scala 对象中模拟函数？

How to mock a function within Scala object using Mockito?

提问by Dilan

I am really new to Scala. I tried to mock a simple Scala function using Mockito, but I get the following error. I have checked the internet but I was unable to find out the error.

我对 Scala 真的很陌生。我尝试使用 Mockito 模拟一个简单的 Scala 函数，但出现以下错误。我已经检查了互联网，但我无法找出错误。

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

And my test class is below

我的测试课在下面

class TempScalaServiceTest extends FunSuite with MockitoSugar{

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

But I get the following error:

但我收到以下错误：

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)

采纳答案by LuisKarlos

You cannot mock objects, try to move your code to a class:

您不能模拟对象，请尝试将您的代码移动到一个类：

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

and create a service:

并创建一个服务：

object TempScalaService {
   private val service = TempScalaService()

   def apply() = service
}

This would be better with a dependency injection framework, but it will work for now.

这对于依赖注入框架会更好，但它现在可以工作。

Now, for the test, use:

现在，对于测试，请使用：

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

回答by Dan Simon

You can define the method in a trait which your object extends. Then simply mock the trait:

您可以在对象扩展的特征中定义方法。然后简单地模拟这个特征：

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]

回答by Gaurav Kumar

You can create a Scala Companion Object:

您可以创建一个 Scala 伴侣对象：

1. Write test cases for you class.
2. Let that object do the external world interaction.

1. 为您的班级编写测试用例。
2. 让那个对象做外部世界的交互。