Scalamock:嘲笑通用案例类导致类型不匹配

Question

我正在使用mongodb作为持久性，目前我正在为我的代码编写测试。我的剪切外观如下

implicit def storageHandler[M[_]: Monad](
    implicit mongoDatabase: MongoDatabase
) = new Storage.Handler[M] {
    override def store(order: Order): M[Unit] = Monad[M].pure {
      val collection: MongoCollection[Document] = mongoDatabase.getCollection("order")
      val document: Document = Document(order.asJson.toString)
      collection.insertOne(document).subscribe((x: Completed) => ())
   }
}

我的模拟是通过使用隐式来正确注入的。我正在嘲笑getCollection呼叫，这本身应该导致另一个模拟，这段时间

MongoCollection[org.mongodb.scala.bson.collection.immutable.Document]

所以我在做的是以下

val mongoCollection: MongoCollection[Document] = mock[MongoCollection[Document]]
(mongoDatabase.getCollection[Document] _).expects("order").once().returning(mongoCollection)

但是，这将导致以下错误

type mismatch;
[error]  found   : com.mongodb.async.client.MongoCollection[TResult]
[error]  required: com.mongodb.async.client.MongoCollection[org.mongodb.scala.bson.collection.immutable.Document]
[error]  val mongoCollection: MongoCollection[Document] = mock[MongoCollection[Document]]

tresult是猫卷的通用参数，看起来像这样：

case class MongoCollection[TResult](private val wrapped: JMongoCollection[TResult]) { 
.... 
}

看来，通用参数未正确"调整"（我不确定如何称呼它）来文档

Answer 1

指定类型参数的预期应起作用，或者，如果您的界面完全抽象，则可以对此使用代理模拟：

import org.scalamock.scalatest.MixedMockFactory
import org.scalatest.{FlatSpec, Matchers}
import scala.reflect.ClassTag
class Issue170Test extends FlatSpec with Matchers with MixedMockFactory {
  behavior of "ScalaMock"
  it should "mock this" in {
    class Foo[T: ClassTag]
    "val m = mock[Foo[Nothing]]" should compile // this one fails :(
  }
  trait TotallyAbstract[T] {
    def foo: Int
    def bar: T
  }
  it should "work with this workaround" in {
    class Foo[T: ClassTag]
    abstract class Foo2 extends Foo[Int] // workaround: specify type parameter
    "val m = mock[Foo2]" should compile
    "val m2 = Proxy.mock[TotallyAbstract[Int]]" should compile
  }
}