如何对Slick 3.x dbio组合器进行单元测试？

Question

我有一个要对它进行单元测试的方法：

@Singleton
class RegistrationWorkflow @Inject()(userService: UserService,
                                 addUserValidator: RegisterUserValidator,
                                 db: Database) {

  def registerUser(registerForm: RegisterUserForm): Future[Vector[FormError]] = {
    val dbActions = addUserValidator.validate(registerForm).flatMap({ validation =>
      if (validation.isEmpty) {
        userService.add(User(GUID.shortGuid(),
          registerForm.username,
          registerForm.email,
          BCrypt.hashpw(registerForm.password, BCrypt.gensalt())))
          .andThen(DBIO.successful(validation))
      } else {
        DBIO.successful(validation)
      }
    }).transactionally
    db.run(dbActions)
  }
}

addUserValidator验证表单并返回Vector表单错误。如果没有错误，则将用户插入数据库。我正在返回表单错误，因为在控制器中我将返回带有错误列表的201或400。

我为此编写了一个specs2测试：

class RegistrationWorkflowTest extends Specification with Mockito with TestUtils {
  "RegistrationControllerWorkflow.registerUser" should {
    "insert a user to database if validation succeeds" in new Fixture {
      registerUserValidatorMock.validate(testUserFormData) returns DBIO.successful(Vector())
      userServiceMock.add(any) returns DBIO.successful(1)
      val result = await(target.registerUser(testUserFormData))

      result.isEmpty must beTrue

      there was one(registerUserValidatorMock).validate(testUserFormData)
      there was one(userServiceMock).add(beLike[User] { case User(_, testUser.username, testUser.email, _) => ok })
    }

    "return error collection if validation failed" in new Fixture {
      registerUserValidatorMock.validate(testUserFormData) returns DBIO.successful(Vector(FormError("field", Vector("error"))))
      val result = await(target.registerUser(testUserFormData))

      result.size must beEqualTo(1)
      result.contains(FormError("field", Vector("error"))) must beTrue

      there was one(registerUserValidatorMock).validate(testUserFormData)
      there was no(userServiceMock).add(any)
    }
  }

  trait Fixture extends Scope with MockDatabase {
    val userServiceMock = mock[UserService]
    val registerUserValidatorMock = mock[RegisterUserValidator]
    val target = new RegistrationWorkflow(userServiceMock, registerUserValidatorMock, db)
    val testUser = UserFactory.baseUser()
    val testUserFormData = RegisterUserFactory.baseRegisterUserForm()
  }
}

该测试的问题在于它仅断言已userService.add被调用。这意味着我可以将实现更改为以下内容：

val dbActions = addUserValidator.validate(registerForm).flatMap({   validation =>
  if (validation.isEmpty) {
    userService.add(User(GUID.shortGuid(),
      registerForm.username,
      registerForm.email,
      BCrypt.hashpw(registerForm.password, BCrypt.gensalt())))
    DBIO.successful(validation)
  } else {
    DBIO.successful(validation)
  }
}).transactionally
db.run(dbActions)

测试仍然可以通过，但是不会插入用户，因为我没有andThen在userService.add方法返回的DBIO上使用组合器。

我知道我可以使用内存数据库，然后断言实际上已插入用户，但是我不想这样做，因为我已经userService.add使用内存数据库分别测试了方法，现在我想测试registerUser方法而无需调用任何方法依赖性。