模拟具有原始类型的案例类 [英] Mocking case classes with primitive types

问题描述

考虑以下类型结构:

trait HasId[T] {
    def id: T
}

case class Entity(id: Long) extends HasId[Long]

比方说，我们想在某些测试中模拟Entity类.

Let's say, we want to mock Entity class in some test.

val entityMock = mock[Entity]
Mockito.when(entityMock.id).thenReturn(0)

播放此类测试结果会引发NullPointerException(第二行)，这可能是由于Scala编译器的行为带有包装原始类型(如果将Long替换为String，则测试可以正确执行).

Playing such test results in throwing NullPointerException (in second line), probably because of scala compiler behaviour with wrapping primitive types (if we replace Long with String, test executes correctly).

An exception or error caused a run to abort. 
java.lang.NullPointerException
at com.test.Entity$MockitoMock$1085095743.id(Unknown Source)
at com.test.Test.<init>(Test.scala:23)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at java.lang.Class.newInstance(Class.java:442)
at org.scalatest.tools.Runner$.genSuiteConfig(Runner.scala:1422)
at org.scalatest.tools.Runner$.$anonfun$doRunRunRunDaDoRunRun$8(Runner.scala:1236)

此错误仅影响大小写类和2.X版本中的模拟.

This error affects only case classes, and mockito in 2.X versions.

有没有已知的解决方案来解决此问题?

Is there any known solution to handle this issue?

更新:在2.0.8-beta之前的版本中出现问题

UPDATE: problem occurs in versions newer than 2.0.8-beta

推荐答案

这是我的测试课程:

import org.mockito.Mockito._
import org.scalatest.mockito.MockitoSugar
import org.scalatest.FlatSpec

class StackOverflowTest extends FlatSpec with MockitoSugar {

  "Bla" should
    "fsg ll ll" in {
      val entityMock = mock[Entity]
      when(entityMock.id).thenReturn(0)
      foo(entityMock)
    }

  def foo(entity: Entity) = {
    entity.id == 0
  }

}

trait HasId[T] {
  def id: T
}

case class Entity(id: Long) extends HasId[Long]

这是我的sbt文件:

name := "scalaExperiments"

version := "0.1"

scalaVersion := "2.12.4"

libraryDependencies += "org.scalatest" %% "scalatest" % "3.0.4" % Test

libraryDependencies += "org.mockito" % "mockito-all" % "2.0.2-beta" % Test

编译并成功通过.

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