EF6嘲讽衍生DbSets [英] EF6 Mocking derived DbSets

问题描述

我想EF6的新嘲讽适用于我现有的代码。

I am trying to apply the new mocking of EF6 to my existing code.

我有一个扩展DbSet类。其中一个方法调用基类（BdSet）创建方法。下面是一个示例代码（不是完整的解决方案或真实姓名）：

I have a class that Extends DbSet. One of the methods call the base class (BdSet) Create method. Here is the a sample code (not the complete solution or real names):

public class DerivedDbSet<TEntity> : DbSet<TEntity>, IKeyValueDbSet<TEntity>, IOrderedQueryable<TEntity> where TEntity : class
{
    public virtual bool Add(string value1, string value2) {
        var entity = Create(); // There is no direct implementation of the Create method it is calling the base method
        // Do something with the values
        this.Add(entity);
        return true;
    }
}

我使用的是测试双打样品嘲讽（这里是代码和平）：

I am mocking using the Test Doubles sample (here is the peace of code):

var data = new List<DummyEntity> {
    new DummyEntity { Value1 = "First", Value2 = "001" },
    new DummyEntity { Value1 = "Second", Value2 = "002" }
}.AsQueryable();
var mock = new Mock<DerivedDbSet<DummyEntity>>();
mock.CallBase = true;
mock.As<IQueryable<T>>().Setup(m => m.Provider).Returns(source.Provider);
mock.As<IQueryable<T>>().Setup(m => m.Expression).Returns(source.Expression);
mock.As<IQueryable<T>>().Setup(m => m.ElementType).Returns(source.ElementType);
mock.As<IQueryable<T>>().Setup(m => m.GetEnumerator()).Returns(source.GetEnumerator());

我已经设置Call​​Base属性设置为true，试图迫使调用基类..

I've set the CallBase property to true to try to force the call to the base class...

不过，我不断收到以下错误：

But I keep receiving the following error:

System.NotImplementedException：成员创建尚未对类型DerivedDbSet 1Proxy'从'DbSet 1继承实施。测试双打DbSet`1必须提供所使用的方法和属性的实现。

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.

我要创建的号召，回退在DbSet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

与内部功能和嘲讽一个DbSet的异步引用一些我挣扎与解决我的大部分问题，并可能作为基础的人实现一个辅助类一经传出。
下面是代码：

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);
    }
}

这是一个利用样本（基于名称我之前已经给）：

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);

关于如何提高该解决方案的任何建议是非常欢迎的。

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

问候

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