如何在使用ADO.NET实体框架时测试业务逻辑(doman模型规则)?

我没有使用实体框架,我也不是100%确定我知道这里发生的事情的全部范围,但是您需要做的是在具有接口的实体框架代码周围放置一个包装器,然后使用模拟框架假装您在实际上没有调用数据库时调用数据库。我会给你一个大概的想法,但是你必须把它应用到实体框架中,因为我不知道细节。

public interface IShareSpaceGateway {
  IEnumerable<ShareSpace> GetSharedSpaces(string spaceToShare, string emailToShareIt);
}

public class ShareSpaceGatewayEF: IShareSpaceGateway
{
  // MySpacesShared should be included up here, not sure what type it is
  public IEnumerable<ShareSpace> GetSharedSpaces(string spaceToShare, string emailToShareIt)
  {
    if (!this.MySpacesShared.IsLoaded) 
     this.MySpacesShared.Load();

    return this.MySpacesShared.Any(s => (s.EmailAddress == emailToShareIt) 
                              & (s.SpaceName == spaceToShare));
  }
}

您可以在isharedspacegateway中使用任何有意义的方法。其目的是减少代码重复。

现在,您希望能够注入对IShareSpaceGateway的新依赖项。使用依赖注入的最佳方法是使用DI容器,如Castle Windsor、结构图、Ninject或Unity。我假设你的代码在这里是什么样子的:

public class Account
{
  private ISharedSpaceGateway _sharedSpaceGateway;
  public Account(ISharedSpaceGateway sharedSpaceGateway)
  {
    _sharedSpaceGateway = sharedSpaceGateway;
  }

  public int ID { get; set; }
  public string Key1 { get; set; }
  public string Key2 { get; set; }
  public string AccountName { get; set; }

  public void ShareSpace(string spaceToShare,string emailToShareIt)
  {
    SharedSpace shareSpace = new SharedSpace();
    shareSpace.InvitationCode = Guid.NewGuid().ToString("N");
    shareSpace.DateSharedStarted = DateTime.Now;
    shareSpace.Expiration = DateTime.Now.AddYears(DefaultShareExpirationInYears);
    shareSpace.Active = true;
    shareSpace.SpaceName = spaceToShare;
    shareSpace.EmailAddress = emailToShareIt;
    var sharedSpaces = sharedSpaceGateway.GetSharedSpaces(spaceToShare, emailToShareIt);
    if(sharedSpaces.Count() > 0)    
      throw new InvalidOperationException("Cannot share the a space with a user twice.");

    this.MySpacesShared.Add(shareSpace);
  }
}

现在,在单元测试中,您希望使用模拟框架(如moq)或Rhinomocks来设置测试。在您的测试中,您不想使用sharedspacegateway的实际实现,而是希望传入一个假的实现。此示例使用犀牛模型

public class TestFixture{


private ISharedSpaceGateway gateway;
[TestInitialize()]
 public void MyTestInitialize() 
 {
    gateway = MockRepository.CreateMock<ISharedSpaceGateway>();
    gateway.Expect(g => g.GetSharedSpaces("spaceName", "user1@domain.com"))
          .Return(new SharedSpace()); // whatever you want to return from the fake call

         user = new User()
         {
                 Active = true,
                 Name = "Main User",
                 UserID = 1,
                 EmailAddress = "user1@userdomain.com",
                 OpenID = Guid.NewGuid().ToString()
         };

         account = new Account(gateway) // inject the fake object
         {
                 Key1 = "test1",
                 Key2 = "test2",
                 AccountName = "Brief Account Description",
                 ID = 1,
                 Owner = user
         };
 }

[TestMethod]
public void Cannot_Share_SameSpace_with_same_userEmail_Twice()
{
        account.ShareSpace("spaceName", "user1@domain.com");
        try
        {
          account.ShareSpace("spaceName", "user1@domain.com");
          Assert.Fail("Should throw exception when same space is shared with same user.");
        }
        catch (InvalidOperationException)
        { /* Expected */ }
        Assert.AreEqual(1, account.MySpacesShared.Count);
        Assert.AreSame(null, account.MySpacesShared.First().InvitedUser);
        gateway.VerifyAllExpectations();
}

使用DI框架和模拟框架涉及很多,但是这些概念使您的代码更易于测试。

从我个人的经验来看,Linq to SQL在编写单元测试方面非常糟糕。

BL层与LINQ to SQL类非常耦合,因为它知道以下概念 .IsLoaded 可以 .Load() 集合等。将此逻辑移动到 ISharedSpacesPersistenceService 重写方法如下:

// Dependency-Inject this
public ISharedSpacesPersistenceService SharedSpacesPersistenceService { get; set; }

public void ShareSpace(string spaceToShare,string emailToShareIt)
{
    SharedSpace shareSpace = new SharedSpace();
    shareSpace.InvitationCode = Guid.NewGuid().ToString("N");
    shareSpace.DateSharedStarted = DateTime.Now;
    shareSpace.Expiration = DateTime.Now.AddYears(DefaultShareExpirationInYears);
    shareSpace.Active = true;
    shareSpace.SpaceName = spaceToShare;
    shareSpace.EmailAddress = emailToShareIt;

    if(SharedSpacesPersistenceService.ContainsSpace(s.EmailAddress, spaceToShare)
        throw new InvalidOperationException("Cannot share the a space with a user twice.");     

    this.MySpacesShared.Add(shareSpace);
}

只是一个小问题:更换 DateTime.Now.AddYears(DefaultShareExpirationInYears) 具有 DateTime.Now.Add(DefaultShareExpiration) 并设置 DefaultShareExpiration 类型到 TimeSpan . 这样会更好。

更好的方法是,您不应该接触由域层中的实体框架生成的类。相反,您应该创建自己的业务层,并使用Linq将生成的类投影到业务对象中。

这样,您可以以更简单的方式设置测试。