EF6 模拟派生的 DbSet

System.NotImplementedException: The member 'Create' has not been implemented on type 'DerivedDbSet1Proxy' which inherits from 'DbSet1'. Test doubles for 'DbSet`1' must provide implementations of methods and properties that are used.

我希望 create 调用回退到 DbSet 中的默认实现.

I want the call of create to fallback to the default implementation in DbSet.

有人可以帮我吗?

推荐答案

在对模拟 DbSet 的内部函数和异步引用进行了一些斗争之后，我提出了一个帮助类，它解决了我的大部分问题，并且可以作为有人执行.代码如下:

After some struggle with the internal functions and async references of mocking a DbSet I came out with a helper class that solved most of my problems and might serve as base to someone implementation. Here is the code:

public static class MockHelper
{
    internal class TestDbAsyncQueryProvider<TEntity> : IDbAsyncQueryProvider {

        private readonly IQueryProvider _inner;

        internal TestDbAsyncQueryProvider(IQueryProvider inner) { _inner = inner; }
        public IQueryable CreateQuery(Expression expression) { return new TestDbAsyncEnumerable<TEntity>(expression); }
        public IQueryable<TElement> CreateQuery<TElement>(Expression expression) { return new TestDbAsyncEnumerable<TElement>(expression); }
        public object Execute(Expression expression) { return _inner.Execute(expression); }
        public TResult Execute<TResult>(Expression expression) { return _inner.Execute<TResult>(expression); }
        public Task<object> ExecuteAsync(Expression expression, CancellationToken cancellationToken) { return Task.FromResult(Execute(expression)); }
        public Task<TResult> ExecuteAsync<TResult>(Expression expression, CancellationToken cancellationToken) { return Task.FromResult(Execute<TResult>(expression)); }
    }

    internal class TestDbAsyncEnumerable<T> : EnumerableQuery<T>, IDbAsyncEnumerable<T> {
        public TestDbAsyncEnumerable(IEnumerable<T> enumerable) : base(enumerable) { }
        public TestDbAsyncEnumerable(Expression expression) : base(expression) { }
        public IDbAsyncEnumerator<T> GetAsyncEnumerator() { return new TestDbAsyncEnumerator<T>(this.AsEnumerable().GetEnumerator()); }
        IDbAsyncEnumerator IDbAsyncEnumerable.GetAsyncEnumerator() { return GetAsyncEnumerator(); }
        public IQueryProvider Provider { get { return new TestDbAsyncQueryProvider<T>(this); } }
    } 

    internal class TestDbAsyncEnumerator<T> : IDbAsyncEnumerator<T> {

        private readonly IEnumerator<T> _inner;

        public TestDbAsyncEnumerator(IEnumerator<T> inner) { _inner = inner; }
        public void Dispose() { _inner.Dispose(); }
        public Task<bool> MoveNextAsync(CancellationToken cancellationToken) { return Task.FromResult(_inner.MoveNext()); }
        public T Current { get { return _inner.Current; } }
        object IDbAsyncEnumerator.Current { get { return Current; } }
    } 

    public static Mock<TDbSet> CreateDbSet<TDbSet, TEntity>(IList<TEntity> data, Func<object[], TEntity> find = null)
        where TDbSet : class, IDbSet<TEntity>
        where TEntity : class, new() {
        var source = data.AsQueryable();
        var mock = new Mock<TDbSet> { CallBase = true };
        mock.As<IQueryable<TEntity>>().Setup(m => m.Expression).Returns(source.Expression);
        mock.As<IQueryable<TEntity>>().Setup(m => m.ElementType).Returns(source.ElementType);
        mock.As<IQueryable<TEntity>>().Setup(m => m.GetEnumerator()).Returns(source.GetEnumerator());
        mock.As<IQueryable<TEntity>>().Setup(m => m.Provider).Returns(new TestDbAsyncQueryProvider<TEntity>(source.Provider));
        mock.As<IDbAsyncEnumerable<TEntity>>().Setup(m => m.GetAsyncEnumerator()).Returns(new TestDbAsyncEnumerator<TEntity>(data.GetEnumerator()));
        mock.As<IDbSet<TEntity>>().Setup(m => m.Create()).Returns(new TEntity());
        mock.As<IDbSet<TEntity>>().Setup(m => m.Add(It.IsAny<TEntity>())).Returns<TEntity>(i => { data.Add(i); return i; });
        mock.As<IDbSet<TEntity>>().Setup(m => m.Remove(It.IsAny<TEntity>())).Returns<TEntity>(i => { data.Remove(i); return i; });
        if (find != null) mock.As<IDbSet<TEntity>>().Setup(m => m.Find(It.IsAny<object[]>())).Returns(find);
        return mock;
    }

    public static Mock<DbSet<TEntity>> CreateDbSet<TEntity>(IList<TEntity> data, Func<object[], TEntity> find = null)
        where TEntity : class, new() {
        return CreateDbSet<DbSet<TEntity>, TEntity>(data, find);
    }
}

这是一个使用示例(基于我之前给出的名称):

And here is a use sample (based on the names I've given before):

var data = new List<DummyEntity> {
    new DummyEntity { Value1 = "First", Value2 = "001" } },
    new DummyEntity { Value1 = "Second", Value2 = "002" } }
};
var mockDummyEntities = MockHelper.CreateDbSet<DerivedDbSet<DummyEntities>, DummyEntities>(data, i => data.FirstOrDefault(k => k.Value2 == (string)i[0]));
var mockContext = new Mock<DummyDbContext>();
mockContext.Setup(c => c.DummyEntities).Returns(mockDummyEntities.Object);

非常欢迎任何有关如何改进此解决方案的建议.

Any suggestions on how to improve this solution is very welcome.

问候

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