scala - 使用scalamock在scala中使用ClassTag的模拟方法

我的第一个问题question已得到回答，但发现了我遇到的另一个问题。这是场景。

示例代码(从上一个问题扩展)

一个模型:

case class User (first: String, last: String, enabled: Boolean)

组件定义:

trait DataProviderComponent {
  def find[T: ClassTag](id: Int): Try[T]
  def update[T](data: T): Try[T]
}

具体的组件实现之一(更新的实现):

class DbProvider extends DataProviderComponent {
  override def find[T: ClassTag](id: Int): Try[T] = {
    Try {
      val gson = new Gson()
      val testJson = """{"first": "doe", "last": "jane", "enabled": false}"""

      gson.fromJson(testJson, implicitly[ClassTag[T]].runtimeClass).asInstanceOf[T]
    }
  }

  override def update[T](data: T): Try[T] = ???
}

组件impl在系统中某处的隐式使用:

implicit val provider = new DbProvider()

class UserRepsitory(implicit provider: DataProviderComponent) {
  def userEnabled(id: Int): Boolean = {
    val user = provider.find[User](id)
    user.isSuccess && user.get.enabled
  }
}

单元Test1，尝试模拟提供程序以隔离存储库测试。这不起作用，运行测试时将引发以下执行。我希望这是因为使用了ClassTag，因为当我创建另一个不使用ClassTag的示例时，它可以正常工作。

org.scalamock.MockFunction2无法转换为org.scalamock.MockFunction1
java.lang.ClassCastException:org.scalamock.MockFunction2无法转换为org.scalamock.MockFunction1

class UserRepository$Test1 extends FunSuite with Matchers with MockFactory {
  test("invalid data request should return false") {
    implicit val mockProvider: DataProviderComponent = mock[DataProviderComponent]
    (mockProvider.find[User] _).expects(13).returns(Failure[User](new Exception("Failed!")))

    val repo = new UserRepsitory()
    repo.userEnabled(13) should be (false)
  }
}

单元Test2确实可以工作，但是很难维护，并且需要更多代码:

class UserRepository$Test2 extends FunSuite with Matchers with MockFactory {
  test("invalid data request should return false") {
    class FakeProvider extends DataProviderComponent {
      override def find[T:ClassTag](id: Int): Try[T] = Failure[T](new Exception("Failed!"))
      override def update[T](data: T): Try[T] = ???
    }

    implicit val provider = new FakeProvider()
    val repo = new UserRepsitory()
    repo.userEnabled(13) should be (false)
  }
}

单元Test3确实可以工作，但是-仅用于测试ClassTag实现:

class UserRepository$Test3 extends FunSuite with Matchers with MockFactory {
  test("prove sut works") {
    implicit val provider = new DbProvider()
    val repo = new UserRepsitory()
    val user = repo.userEnabled(13)
    println(user.toString)
  }
}

我使用ClassTag错误还是模拟无法正确模拟？

最佳答案

这类似于:ScalaMock User Guide: Mocking methods with implicit params-有一个隐式的ClassTag参数，因此您必须说服
Scala编译器应将find[T](id:Int)(m: ClassTag[T])转换为MockFunction2
以下代码可用于ScalaMock 3.2:

package com.paulbutcher.test.mock

import org.scalamock.scalatest.MockFactory
import org.scalatest.{ FlatSpec, ShouldMatchers }

import scala.reflect.ClassTag
import scala.util.{ Failure, Try }

case class User(first: String, last: String, enabled: Boolean)

trait DataProviderComponent {
  def find[T: ClassTag](id: Int): Try[T]
  def update[T](data: T): Try[T]
}

class UserRepsitory(implicit provider: DataProviderComponent) {
  def userEnabled(id: Int): Boolean = {
    val user = provider.find[User](id)
    user.isSuccess && user.get.enabled
  }
}

class ClassTagTest extends FlatSpec with ShouldMatchers with MockFactory {
  behavior of "ScalaMock"

  it should "handle mocking methods with class tags" in {
    implicit val mockProvider: DataProviderComponent = mock[DataProviderComponent]
    (mockProvider.find[User](_: Int)(_: ClassTag[User])).expects(13, *).returns(Failure[User](new Exception("Failed!")))

    val repo = new UserRepsitory()
    repo.userEnabled(13) should be(false)
  }
}