如何模拟实体框架6异步方法？ [英] How to mock Entity Framework 6 Async methods?

问题描述

我是新的嘲弄。我想嘲笑我的基础信息库是依赖于实体框架6的DbContext，但我失败了。我在谷歌搜索了很多，但没有得到任何充分的结果。最后，我得到了一个例子，在测试与异步查询并努力遵循，但它工作了我的。

I am new in mocking. I want to mock up my base repository which is depend on Entity Framework 6 DbContext But I fail. I searched in Google a lot but did not get any sufficient result. At last I got an example at testing with async queries and try to follow but it is worked for me.

下面是我的code：

的DbContext：

DbContext :

public class TimeSketchContext : DbContext
{
    public virtual DbSet<EmployeeSkill> EmployeeSkill { get; set; }
}

基础信息库：

Base Repository :

public class BaseRepository<T> : IRepositoryBase<T> where T : class, IEntity, new()
{
    protected readonly DbContext InnerDbContext;
    protected DbSet<T> InnerDbSet;

    public BaseRepository(DbContext innerDbContext)
    {
        InnerDbContext = innerDbContext;
        InnerDbSet = InnerDbContext.Set<T>();
    }

    public virtual Task<T> FindAsync(long id)
    {
        return InnerDbSet.FirstOrDefaultAsync(x=>x.Id == id);
    }

}

测试：

    [Fact]
    public async Task DbTest()
    {
        var dummyData = GetEmployeeSkills();
        var mockSet = new Mock<DbSet<EmployeeSkill>>();

        mockSet.As<IDbAsyncEnumerable<EmployeeSkill>>()
            .Setup(x => x.GetAsyncEnumerator())
            .Returns(new TestDbAsyncEnumerator<EmployeeSkill>(dummyData.GetEnumerator()));

        mockSet.As<IQueryable<EmployeeSkill>>()
            .Setup(x => x.Provider)
            .Returns(new TestDbAsyncQueryProvider<EmployeeSkill>(dummyData.Provider));

        mockSet.As<IQueryable<EmployeeSkill>>().Setup(m => m.Expression).Returns(dummyData.Expression);
        mockSet.As<IQueryable<EmployeeSkill>>().Setup(m => m.ElementType).Returns(dummyData.ElementType);
        mockSet.As<IQueryable<EmployeeSkill>>().Setup(m => m.GetEnumerator()).Returns(dummyData.GetEnumerator());

        var mockContext = new Mock<TimeSketchContext>();
        mockContext.Setup(c => c.EmployeeSkill).Returns(mockSet.Object);

        var baseRepository = new BaseRepository<EmployeeSkill>(mockContext.Object);

        var data = await baseRepository.FindAsync(1);

        Assert.NotEqual(null, data);

    }

    private EmployeeSkill GetEmployeeSkill()
    {
        return new EmployeeSkill
        {
            SkillDescription = "SkillDescription",
            SkillName = "SkillName",
            Id = 1
        };
    }

    private IQueryable<EmployeeSkill> GetEmployeeSkills()
    {
        return new List<EmployeeSkill>
        {
            GetEmployeeSkill(),
            GetEmployeeSkill(),
            GetEmployeeSkill(),
        }.AsQueryable();
    }

结果是：

Assert.NotEqual（）失败

Assert.NotEqual() Failure

我觉得问题是

 public BaseRepository(DbContext innerDbContext)
 {
     InnerDbContext = innerDbContext;
     InnerDbSet = InnerDbContext.Set<T>();  <<<<<<<<<<<
 }

但不`吨明白为什么，以及如何解决这个问题。

But don`t understand why and how to solve this.

我使用的：

• 的Visual Studio 2013旗舰版
• 起订量
• 的xUnit

Thank`s提前。

Thank`s in advance.

推荐答案

您的权利与你的 InnerDbContext.Set＆LT的问题; T＆GT;（）; 语句。

You are right the problem in with your InnerDbContext.Set<T>(); statement.

在EF（6.0.2）中的 DbContext.Set＆LT; T＆GT; 方法是不可以 虚拟所以不能用嘲笑起订量。

In the current version of the EF (6.0.2) the DbContext.Set<T> method is not virtual so it cannot be mocked with Moq.

所以，你不能轻易地让你的测试通过execpt改变你的 BaseRepository 的设计不依赖于整个的DbContext 但有一个 DbSet＆LT; T＆GT; ：

So you cannot easily making your test pass execpt changing your design of the BaseRepository to not depend on the whole DbContext but on one DbSet<T>:

所以是这样的：

public BaseRepository(DbSet<T> dbSet)
{
    InnerDbSet = dbSet;
}

然后你就可以在你的嘲笑Dbset直接通过。

Then you can pass directly in your mocked Dbset.

或者你可以创建一个包装接口的DbContext ：

Or you can create a wrapper interface for DbContext:

public interface IDbContext
{
    DbSet<T> Set<T>() where T : class;
}

public class TimeSketchContext : DbContext, IDbContext
{
    public virtual DbSet<EmployeeSkill> EmployeeSkill { get; set; }
}

然后使用 IDbContext 在 BaseRepository ：

public class BaseRepository<T> : IRepositoryBase<T> where T : class, IEntity, new()
{
    protected readonly IDbContext InnerDbContext;
    protected DbSet<T> InnerDbSet;

    public BaseRepository(IDbContext innerDbContext)
    {
        InnerDbContext = innerDbContext;
        InnerDbSet = InnerDbContext.Set<T>();
    }

    public virtual Task<T> FindAsync(long id)
    {
        return InnerDbSet.FirstOrDefaultAsync(x => x.Id == id);
    }
}

最后，你只需要改变两行的测试，使其通过：

And finally you just need to change two lines in your test to make it pass:

var mockContext = new Mock<IDbContext>();
mockContext.Setup(c => c.Set<EmployeeSkill>()).Returns(mockSet.Object);

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