测试和模拟私有/受保护的方法.许多帖子但仍然无法使一个例子有效

Question

我已经看过许多关于"嘲弄私有方法"的帖子和问题,但仍然无法使其工作而没有找到真正的答案.让我们忘记代码的味道,你不应该这样做....

根据我的理解,我做了以下事情:

1)创建了一个类库"MyMoqSamples"

2)添加了对Moq和NUnit的引用

3)编辑AssemblyInfo文件并添加[assembly:InternalsVisibleTo("DynamicProxyGenAssembly2")] [assembly:InternalsVisibleTo("MyMoqSamples")]

4)现在需要测试私有方法.因为它是私有方法,所以它不是接口的一部分.

5)添加以下代码

[TestFixture]
public class Can_test_my_private_method
{
    [Test]
    public void Should_be_able_to_test_my_private_method()
    {
        // TODO how do I test my DoSomthing method?
    }
}

public class CustomerInfo
{
    public string Name { get; set; }
    public string Surname { get; set; }
}

public interface ICustomerService
{
    List<CustomerInfo> GetCustomers();
}

public class CustomerService : ICustomerService
{
    public List<CustomerInfo> GetCustomers()
    {
        return new List<CustomerInfo> { new CustomerInfo { Surname = "Bloggs", Name = "Jo" } };
    }

    protected virtual void DoSomething()
    {
    }
}

你能举例说明你如何测试我的私有方法吗？非常感谢

Answer 1

您描述的步骤将Moq设置为测试内部类和成员,因此与测试受保护或私有方法没有任何关系

测试私有方法有点气味,你应该真正测试公共API.如果您认为该方法非常重要并且需要单独进行测试,那么它是否应该属于自己的类,然后可以自行测试？

如果您的心脏已经开始测试上面的受保护方法,那么您可以在测试程序集中滚动自己的Mock:

public class CustomerServiceMock : CustomerService {
    public void DoSomethingTester() {
         // Set up state or whatever you need
         DoSomething();
    }

}

[TestMethod]
public void DoSomething_WhenCalled_DoesSomething() {
    CustomerServiceMock serviceMock = new CustomerServiceMock(...);
    serviceMock.DoSomethingTester();
 }

如果它是私人的,你可能会做一些狡猾的反思,但走这条路是测试地狱的方法.

更新

虽然你已经在你的问题中给出了示例代码,但我并没有真正看到你想如何"测试"受保护的方法,所以我会想出一些人为的...

假设您的客户服务如下: -

 public CustomerService : ICustomerService {

      private readonly ICustomerRepository _repository;

      public CustomerService(ICustomerRepository repository) {
           _repository = repository;
      } 

      public void MakeCustomerPreferred(Customer preferred) {
           MakePreferred(customer);
           _repository.Save(customer);
      }

      protected virtual void MakePreferred(Customer customer) {
          // Or more than likely some grungy logic
          customer.IsPreferred = true;
      }
 }

如果您想测试受保护的方法,您可以执行以下操作: -

[TestClass]
public class CustomerServiceTests {

     CustomerServiceTester customerService;
     Mock<ICustomerRepository> customerRepositoryMock;

     [TestInitialize]
     public void Setup() {
          customerRepoMock = new Mock<ICustomerRepository>();
          customerService = new CustomerServiceTester(customerRepoMock.Object);
     }


     public class CustomerServiceTester : CustomerService {    
          public void MakePreferredTest(Customer customer) {
              MakePreferred(customer);
          }

          // You could also add in test specific instrumentation
          // by overriding MakePreferred here like so...

          protected override void MakePreferred(Customer customer) {
              CustomerArgument = customer;
              WasCalled = true;
              base.MakePreferred(customer);
          }

          public Customer CustomerArgument { get; set; }
          public bool WasCalled { get; set; }
     }

     [TestMethod]
     public void MakePreferred_WithValidCustomer_MakesCustomerPreferred() {
         Customer customer = new Customer();
         customerService.MakePreferredTest(customer);
         Assert.AreEqual(true, customer.IsPreferred);
     }

     // Rest of your tests
}

这个"模式"的名称是Test特定的子类(基于xUnit测试模式术语),您可能希望在此处看到更多信息: -

http://xunitpatterns.com/Test-Specific%20Subclass.html

根据您的评论和之前的问题,您似乎已经承担了对某些遗留代码实施单元测试(或自己做出决定)的任务.在这种情况下,所有遗留代码的圣经都是Michael Feathers的书.它涵盖了这样的技术以及重构和技术,以处理将"不可测试的"类和方法分解为更易于管理的东西,我强烈推荐它.