c# - 最小起订量 - 使用 DbEntityEntry 更新

Question

我正在使用 EF6。生成的代码类似于:

public partial class MyDataContext : DbContext
{
    public MyDataContext() : base("name=mydata")
    {
    }

    public virtual DbSet<Book> Books { get; set; }
}

然后我有一个通用的存储库，例如:

public class GenericRepository<TObject> where TObject : class
{
    protected readonly MyDataContext Context;

    protected GenericRepository(MyDataContext context)
    {
        Context = context;
    }

    public virtual TObject Update(TObject data, int id)
    {
        if (data == null)
            return null;

        TObject obj = Context.Set<TObject>().Find(id);
        if (obj != null)
        {
            Context.Entry(obj).CurrentValues.SetValues(data);
            Context.SaveChanges();
        }

        return obj;
    }
}

然后我有一个使用 GenericRepository 来更新数据的服务:

public class MyDataService<TObject> where TObject : class
{
    private readonly MyDataContext context;

    public MyDataService(MyDataContext ct)
    {
        context = ct;
    }

    public TObject Update(TObject obj, int id)
    {
        var r = new GenericRepository<TObject>(context);
        return r.Update(obj, id);
    }
}

所以我可以用这样的东西更新一本书:

var ds = new MyDataService<Book>(new MyDataContext());
var data = ds.Update(new Book { Name = "New Name" }, 1);

这工作正常。接下来，我尝试使用 Moq 对上面的代码进行单元测试，例如:

var updatedBook = new Book { Name = "Update Book Name" };

var mockSet = new Mock<DbSet<Book>>();
var mockContext = new Mock<MyDataContext>();
mockContext.Setup(c => c.Books).Returns(mockSet.Object);
mockContext.Setup(c => c.Set<Book>().Find(It.IsAny<object[]>()))
            .Returns<object[]>(ids => chips.FirstOrDefault(d => d.Id == (int)ids[0]));

var service = new MyDataService<Book>(mockContext.Object);
var data = service.Update(updatedBook, 1);

但是，我在 Context.Entry(obj).CurrentValues.SetValues(data) 行遇到异常。

如何正确模拟 Update 方法？

Answer 1

你可以为 MyDataService 实现一个接口(interface)来模拟它

public Interface IMyDataService<TObject> where TObject : class
{
   TObject Update(TObject obj, int id);
}

public class MyDataService<TObject>:IMyDataService<TObject>
 where TObject : class
{
    private readonly MyDataContext context;

    public MyDataService(MyDataContext ct)
    {
        context = ct;
    }

    public TObject Update(TObject obj, int id)
    {
        var r = new GenericRepository<TObject>(context);
        return r.Update(obj, id);
    }
}

起订量:

var mockDataService = new  Mock<IMyDataService<Book>>();
mockDataService.Setup(c=> c.Update(It.Any<Book>(),It.Any<int>()).Returns(updatedbook);