使用Moq模拟要测试的对象的依赖关系时出现类型错误

Question

我有一个验证类，我正在尝试测试FluentQuestionAnswerValidator ，但是此类具有依赖项IQuestionAnswerRepository ，必须将其通过构造函数传递才能实例化验证器类。

为了尝试实例化该类，我使用Moq来模拟存储库，然后可以将其传递给验证器。

但是，当我尝试在实例化实例库时将模拟的存储库传递到验证器时，出现类型错误：

Error   CS1503  Argument 2: cannot convert from 
'Moq.Mock<IQuestionAnswerRepository>' to 'IQuestionAnswerRepository'    

如何更改已有的代码，以使其接受模拟的存储库作为其依赖项？

class QuestionAnswerValidationTest
    {
        private QuestionAnswer _qaTest;
        private FluentQuestionAnswerValidator _validator;
        private Mock<IQuestionAnswerRepository> mockRepo;

        [SetUp]
        public void Setup()
        {
            _qaTest = new QuestionAnswer()
            {
                Id = 2,
                Type = "Number",
                Required = true,
                QuestionSection = 1,
            };

            QuestionAnswer qa = new QuestionAnswer()
            {
                Id = 1,
                Type = "String",
                Required = true,
                QuestionSection = 1,
                Answer = "Yes",
                ConditionalQuestionId = null,
                ConditionalQuestionAnswered = null
            };

            Dictionary<int, QuestionAnswer> questionMap = new Dictionary<int, QuestionAnswer>();
            questionMap.Add(qa.Id, qa);

            mockRepo = new Mock<IQuestionAnswerRepository>(MockBehavior.Strict);
            mockRepo.Setup(p => p.QuestionMap).Returns(questionMap);
        }

        [Test]
        public void Validate_AnswerDoesNotMatchQuestionType_ProducesValidationError()
        {
            _qaTest.Answer = "string";

            _validator = new FluentQuestionAnswerValidator(_qaTest, mockRepo);
        }
    }

Answer 1

您的FluentQuestionAnswerValidator显然希望使用IQuestionAnswerRepository实例，而不是Mock<IQuestionAnswerRepository>实例。 由于这两者之间没有隐式转换，因此会出现错误。

因此，您实际上想要提供的不是模拟本身，而是由框架创建的实例 。 所以改用这个：

_validator = new FluentQuestionAnswerValidator(_qaTest, mockRepo.Object);