使用IQueryable< TEntity>而是DbSet< TEntity>问题 [英] Using IQueryable<TEntity> instead DbSet<TEntity> problem
问题描述
我偶然发现下一个问题...我有数据库上下文：
i stumbled to the next problem... I have database context:
// For support unit testing...
public interface IDbContext : IDisposable
{
IQueryable<Hardware> Hardwares { get; }
IQueryable<ProviderHardware> ProviderHardwares { get; }
}
// Real DbContext (EF 4.0, Code First)
public class PrimaryDbContext : DbContext, IDbContext
{
public DbSet<Hardware> Hardwares { get; set; }
public DbSet<ProviderHardware> ProviderHardwares { get; set; }
IQueryable<Hardware> IDbContext.Hardwares
{ get { return Hardwares; } }
IQueryable<ProviderHardware> IDbContext.ProviderHardwares
{ get { return ProviderHardwares; } }
...
}
然后我尝试获取所有硬件，
And i try get all hardwares, which doesnt exists in ProviderHardwares table:
var hardwaresRemoved = db.Hardwares.Where(i => (i.IsAvailable == true) &&
(db.ProviderHardwares.Count(j => j.Article == i.Article) == 0)).ToList();
如果我严格使用PrimaryDbContext，例如 PrimaryDbContext db = new PrimaryDbContext（）;一切正常。但是，如果我隐式使用它，则 IDbContext db = new PrimaryDbContext（）;我得到一个例外：
If i use PrimaryDbContext strictly such as "PrimaryDbContext db = new PrimaryDbContext();" all work fine. But if i use it implicitly "IDbContext db = new PrimaryDbContext();" that i get an exception:
无法创建类型为
的常量值 ConfiguratorMvcApplication.DomainModels.ProviderHardware。在这种情况下，
仅支持
基本类型（例如Int32，String和Guid）。
Unable to create a constant value of type 'ConfiguratorMvcApplication.DomainModels.ProviderHardware'. Only primitive types ('such as Int32, String, and Guid') are supported in this context.
<总结一下，我无法替换IQueryable上的DbSet。在这种情况下，我该如何使用单元测试？我希望有人解决了这个问题...
非常感谢！
Summarize, i can't replace a DbSet on an IQueryable. And how i can use unit testing in this case? I hope someone have resolved this problem yet... Thank in advance very much!
推荐答案
我建议您更好保留DbSet并进行集成测试 包括 数据库。
I suggest you better keep DbSets and do INTEGRATION TESTING including the database.
因为，尽管通过了带有数据库模拟的单元测试可能会有些用，在真实数据库上进行测试会更好（但不是单元测试）。
Because, although passing a unit test with a mock of a DB could be somewhat usefull, you are going to be better off testing with real database (but it's not unit testing).
ClassInitialize擦除数据库和/或创建用于测试的初始数据。
On the ClassInitialize erase the database and/or create the initial data for testing.
如果您创建带有连接字符串的App.config文件，则可以拥有单独的测试数据库，并且如果您使用的是EF Code First，则可以免费获得。
If you create an App.config file with a connection string you can have a separate test database, and if you are using EF Code First, you get it for free.
最诚挚的问候。
这篇关于使用IQueryable< TEntity>而是DbSet< TEntity>问题的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
