使用AutoMapper ProjectTo和Moq.EntityFrameworkCore进行单元测试

// 定义源类型和目标类型
public class SourceEntity
{
    public int Id { get; set; }
    public string Name { get; set; }
}

public class DestinationDto
{
    public int Id { get; set; }
    public string Name { get; set; }
}

// 定义AutoMapper映射规则
public class MappingProfile : Profile
{
    public MappingProfile()
    {
        CreateMap<SourceEntity, DestinationDto>();
    }
}

// 编写需要测试的服务或方法
public class MyService
{
    private readonly DbContext _dbContext;
    private readonly IMapper _mapper;

    public MyService(DbContext dbContext, IMapper mapper)
    {
        _dbContext = dbContext;
        _mapper = mapper;
    }

    public IEnumerable<DestinationDto> GetEntities()
    {
        var entities = _dbContext.Set<SourceEntity>().AsQueryable();
        var dtos = entities.ProjectTo<DestinationDto>(_mapper.ConfigurationProvider);
        return dtos;
    }
}

// 编写单元测试
[TestClass]
public class MyServiceTests
{
    [TestMethod]
    public void GetEntities_Should_Return_DestinationDtos()
    {
        // 创建模拟的DbContext对象并填充模拟数据
        var dbContextMock = new Mock<DbContext>();
        var sourceEntities = new List<SourceEntity>
        {
            new SourceEntity { Id = 1, Name = "Entity 1" },
            new SourceEntity { Id = 2, Name = "Entity 2" }
        };
        var sourceDbSetMock = new Mock<DbSet<SourceEntity>>();
        sourceDbSetMock.As<IQueryable<SourceEntity>>().Setup(m => m.Provider).Returns(sourceEntities.AsQueryable().Provider);
        sourceDbSetMock.As<IQueryable<SourceEntity>>().Setup(m => m.Expression).Returns(sourceEntities.AsQueryable().Expression);
        sourceDbSetMock.As<IQueryable<SourceEntity>>().Setup(m => m.ElementType).Returns(sourceEntities.AsQueryable().ElementType);
        sourceDbSetMock.As<IQueryable<SourceEntity>>().Setup(m => m.GetEnumerator()).Returns(sourceEntities.AsQueryable().GetEnumerator());
        dbContextMock.Setup(m => m.Set<SourceEntity>()).Returns(sourceDbSetMock.Object);

        // 创建模拟的Mapper对象
        var mapperMock = new Mock<IMapper>();
        mapperMock.Setup(m => m.ConfigurationProvider).Returns(new MapperConfiguration(cfg => cfg.AddProfile<MappingProfile>()));

        // 创建需要测试的服务并注入模拟的DbContext和Mapper对象
        var service = new MyService(dbContextMock.Object, mapperMock.Object);

        // 调用需要测试的方法
        var result = service.GetEntities();

        // 断言验证结果
        Assert.AreEqual(2, result.Count());
        Assert.AreEqual(1, result.First().Id);
        Assert.AreEqual("Entity 1", result.First().Name);
        Assert.AreEqual(2, result.Last().Id);
        Assert.AreEqual("Entity 2", result.Last().Name);
    }
}