Net Core：如何使用数据库行简单地对存储库和服务进行单元测试

Question

我在实体框架中有一个模型。我想确保应用程序服务正在正确读取指向数据库的通用存储库。我该如何在 Xunit 中测试这个，我有点卡住了？收到以下错误，也许我需要重写代码。需要验证应用程序服务可以读取 InMemorydatabase 中下面的示例数据行。

模型：

public partial class Department
{
    public int DepartmentId { get; set; }
    public string DepartmentCode { get; set; }
    public string DepartmentName { get; set; }
    .... plus additional
}

数据传输对象：

public class DepartmentDto
{
    public int DepartmentId { get; set; }
    public string DepartmentCode { get; set; }
    public string DepartmentName { get; set; }
}

IRepository 的基础存储库：

    public async Task<T> GetAsync(int id)
    {
        return await Table.FindAsync(id);
    }

**Constructor:**

    public BaseRepository(DbContext context)
    {
        _context = context;
        Table = _context.Set<T>();
    }

服务：DepartmentAppService.cs

    public async Task<DepartmentDto> GetDepartmentById(int id)
    {
        var department = await departmentRepository.GetAsync(id);
        var departmentDto = mapper.Map<Department, DepartmentDto>(department);
        return departmentDto;
    }

**Constructor:**

   public DepartmentAppService(IRepository<Department> departmentRepository, IMapper mapper)
    {
        this.departmentRepository = departmentRepository;
        this.mapper = mapper;
    }

尝试的测试代码：

public async Task Get_DepartmentById_Are_Equal()
    {
        var options = new DbContextOptionsBuilder<TestContext>()
            .UseInMemoryDatabase(databaseName: "TestDatabase")
            .Options;

        var context = new TestContext(options);

        Mock<IRepository<Department>> departmentRepositoryMock = new Mock<IRepository<Department>>();
        Mock<IMapper> mapperMock = new Mock<IMapper>();
        Mock<DepartmentAppService> departmentAppServiceMock = new Mock<DepartmentAppService>(departmentRepositoryMock, mapperMock);

        context.Department.Add(new Department { DepartmentId = 2, DepartmentCode = "123", DepartmentName = "ABC" });

        var test = await departmentAppServiceMock.GetDepartmentById(5);

        Assert.Equal("123", test.DepartmentCode);

接收错误：如何修复？

'Mock<DepartmentAppService>' does not contain a definition for 'GetDepartmentById' and no accessible extension method 'GetDepartmentById' accepting a first argument of type 'Mock<DepartmentAppService>' could be found (are you missing a using directive or an assembly reference?)  

程序中也有依赖注入。允许根据需要重写代码，

Answer 1

您不想创建DepartmentAppService. 您想要创建一个实例。您正在测试的方法需要真实对象的实例，而不是模拟对象。您想要测试实际对象的代码，模拟不运行任何代码，而只返回假数据。

        var config = new MapperConfiguration(cfg =>
        {
            cfg.AddProfile(sharedServicesProfile);
        });
        mapper = config.CreateMapper();

var departmentAppService = new DepartmentAppService(departmentRepositoryMock.Object, mapperMock.Object);

如果您正在使用 InMemory 数据库，并且实际上是从该 InMemory 数据库获取存储库的数据，那么您也不想模拟您的存储库，因为您正在访问物理数据库并返回真实数据而不是模拟数据。

老实说，我认为您需要更多地阅读有关测试和模拟的内容。看起来缺少一些核心概念......这是编写您想要做的事情的一种方式。

AutoMapper.Mapper.Initialize(m => m.AddProfile<YOUR AUTOMAPPER PROFILE>());
AutoMapper.Mapper.AssertConfigurationIsValid();
var options = new DbContextOptionsBuilder<TestContext>()
        .UseInMemoryDatabase(databaseName: "TestDatabase")
        .Options;

var context = new TestContext(options))
context.Department.Add(new Department { DepartmentId = 2, DepartmentCode = "123", DepartmentName = "ABC" });
context.SaveChanges();    

var departmentRepository = new Repository<Department>>(context);
var departmentAppService = new DepartmentAppService(departmentRepository, mapper);

var test = await departmentAppService.GetDepartmentById(5);

Assert.Equal("123", test.DepartmentCode);

您可能还需要考虑处理您的上下文或将其包装在 using 中。如果复制粘贴后代码无法正确运行，则可能需要进行一些调整，但它应该相当接近。

从上面的代码中可以看出，您仍然需要学习何时进行模拟，何时不进行模拟！不需要模拟。您还在进行集成测试，如果您不想进行集成测试，您可以删除上下文内容并模拟存储库并设置模拟以返回部门。