c# - 最小起订量 : Property is correctly set as virtual but still have invalid setup on a non-virtual member

Question

我想对继承自 IdentityDbContext 的 DbContext 进行单元测试

我收到一条 NotSupportedException 错误消息，其中包含非常常见的消息:

System.NotSupportedException: Invalid setup on a non-virtual (overridable in VB) member

为了找到一些线索，我已经阅读了很多帖子。以下是一些示例:

• This post

• This other post

• This Last one

显然，解决方案似乎是将 dbSet 设置为虚拟的。我做了什么。

运气不好，错误依旧。

这是我的IdentityDataContext:

public class IdentityDataContext : IdentityDbContext<ApplicationUser>
{      
    public virtual DbSet<Search> Searches { get; set; }

    public IdentityDataContext()
        : base("LocalDb",
              throwIfV1Schema: true)
    {            
    }

    public static IdentityDataContext Create()
    {
        return new IdentityDataContext();
    }
}

这是我的搜索 POCO:

public class Search : BaseEntity
{
    //BaseEntity is just an abstract class with createdAt,Id,updatedAt property
    public string ConsumerIdentifier { get; set; }
    public string LanguageCode { get; set; }         
}

最后是我的设置方法:

[TestInitialize]
public void SetupTest()
{
    //DataInitializer.GetAllSearches() returns a List of "Search"

    _searches = DataInitializer.GetAllSearches();

    var dbSet = new Mock<DbSet<Search>>();
    dbSet.As<IQueryable<Search>>().Setup(m => m.Provider).Returns(_searches.AsQueryable().Provider);
    dbSet.As<IQueryable<Search>>().Setup(m => m.Expression).Returns(_searches.AsQueryable().Expression);
    dbSet.As<IQueryable<Search>>().Setup(m => m.ElementType).Returns(_searches.AsQueryable().ElementType);
    dbSet.As<IQueryable<Search>>().Setup(m => m.GetEnumerator()).Returns(_searches.AsQueryable().GetEnumerator());
    dbSet.Setup(d => d.Add(It.IsAny<Search>())).Callback<Search>(_searches.Add);

    _dataContextMock = new Mock<IdentityDataContext>()
    {
        CallBase = true
    };

    // The error appears here ---------------- _
    dataContextMock.Setup(x   => x.Searches).Returns(dbSet.Object);
    //----------------------------------------------------------------------

    _dataContextMock.Setup(x => x.Set<Search>()).Returns(dbSet.Object);

    _searchRepository = new SearchRepository(_dataContextMock.Object);
}

我错过了什么？

Answer 1

1) 无需对 DbContext 进行单元测试。微软早就对其进行了广泛的测试。

2) 如果要将 DbContext 用作另一个类的依赖项，则抽象 dbcontext

public interface IDataContext {
    DbSet<Search> Searches { get; set; }
}

public class IdentityDataContext : IdentityDbContext<ApplicationUser>, IDataContext { ... }

public class SearchRepository {
    public SearchRepository(IDataContext context) { ... }
}

不要让你的类(class)依赖于具体化，而是依赖于抽象。 IdentityDataContext 是依赖类不需要知道的实现细节。

这将允许更灵活的测试

Mock<IDataContext> _dataContextMock;

[TestInitialize]
public void SetupTest() {

    //DataInitializer.GetAllSearches() returns a List of "Search"
    _searches = DataInitializer.GetAllSearches();
    var queryable = _searches.AsQueryable();

    var dbSet = new Mock<DbSet<Search>>();
    dbSet.As<IQueryable<Search>>().Setup(m => m.Provider).Returns(queryable.Provider);
    dbSet.As<IQueryable<Search>>().Setup(m => m.Expression).Returns(queryable.Expression);
    dbSet.As<IQueryable<Search>>().Setup(m => m.ElementType).Returns(queryable.ElementType);
    dbSet.As<IQueryable<Search>>().Setup(m => m.GetEnumerator()).Returns(() => queryable.GetEnumerator());
    dbSet.Setup(d => d.Add(It.IsAny<Search>())).Callback<Search>(_searches.Add);


    _dataContextMock = new Mock<IDataContext>();

    _dataContextMock.Setup(x => x.Searches).Returns(dbSet.Object);

    _dataContextMock.Setup(x => x.Set<Search>()).Returns(dbSet.Object);

    _searchRepository = new SearchRepository(_dataContextMock.Object);

}