EF Entry.State上的单元测试失败

Question

有可能进行单元测试吗？

public class MyRepository<T> where T : IdentityUser, new()
{
   public async Task UpdateAsync(T user)
    {
        _context.Entry(user).State = EntityState.Modified;
        _context.Entry(user).Property("UserName").IsModified = false;
        await _context.SaveChangesAsync();
    }
}

[TestInitialize]将1个用户添加到存储库

_user = new IdentityUser { Id = "70a038cdde40" };

IDbSet<IdentityUser> users = new FakeDbSet<IdentityUser> { _user };

var dbContext = new Mock<MyDbContext<IdentityUser>>();
dbContext.Setup(x => x.Users).Returns(() => users);

_repository = new MyRepository<IdentityUser>(dbContext.Object);

而我正试着用这个来测试

private MyRepository<IdentityUser> _repository;

[TestMethod]
public async Task UpdateUser_Success2()
{
    var user = await _repository.FindByIdAsync("70a038cdde40");
    Assert.IsFalse(user.EmailConfirmed, "User.EmailConfirmed is True");

    user.EmailConfirmed = true;

    await _repository.UpdateAsync(user);

    (...)
}

但它死在UpdateAsync的第一行.测试是错误的还是UpdateAsync实现？有什么方法可以测试吗？

编辑

我按照Belogix的建议添加了

 dbContext.Setup(x => x.Entry(It.IsAny<IdentityUser>()))
                       .Returns(() => dbContext.Object.Entry(_user));

我认为这让我更接近,但仍然存在非虚拟错误:非虚拟成员上的设置无效:x => x.Entry(It.IsAny())

Answer 1

有史以来最好的报价:"计算机科学中的所有问题都可以通过另一层次的间接解决" - 巴特勒兰普森.

看起来如果不添加一些额外的抽象就无法直接测试.我必须以这种方式重构我的UpdateAsync方法

public async Task UpdateAsync(T user)
{
    SetEntityStateModified(user);
    SetPropertyIsModified(user);
    await _context.SaveChangesAsync();
}

public virtual void SetPropertyIsModified(T user)
{
    _context.Entry(user).Property("UserName").IsModified = false;
}

public virtual void SetEntityStateModified(T user)
{
    _context.Entry(user).State = EntityState.Modified;
}

然后在Initialize中更新我的测试代码

_repository = new Mock<MyRepository<IdentityUser>>(dbContext.Object);
_repository.Setup(x => x.SetEntityStateModified(It.IsAny<IdentityUser>()));
_repository.Setup(x => x.SetPropertyIsModified(It.IsAny<IdentityUser>()));

我的测试终于过去了

[TestMethod]
public async Task can_update_user_details()
{
    //Arrange
    var user = await _repository.Object.FindByIdAsync("70a038cdde40");
    Assert.IsFalse(user.EmailConfirmed, "User.EmailConfirmed is True");

    //Act            
    user.EmailConfirmed = true;

    await _repository.Object.UpdateAsync(user);
    var newUser = await _repository.Object.FindByIdAsync("70a038cdde40");

    //Assert
    Assert.IsTrue(newUser.EmailConfirmed, "User.EmailConfirmed is False");
}