EntityFrameworkCore中的IDbAsyncQueryProvider

本文介绍了EntityFrameworkCore中的IDbAsyncQueryProvider的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我正在使用XUNIT在点网核心应用程序中进行测试.

I'm using XUNIT to test in a dot net core application.

我需要测试一个在数据上下文中内部对DbSet进行异步查询的服务.

I need to test a service that is internally making an async query on a DbSet in my datacontext.

我在这里看到，可以异步嘲笑DbSet

I've seen here that mocking that DbSet asynchronously is possible.

我遇到的问题是IDbAsyncQueryProvider在我正在使用的EntityframeworkCore中似乎不可用.

The problem I'm having is that the IDbAsyncQueryProvider does not seem to be available in EntityframeworkCore, which I'm using.

我在这里不正确吗?其他人有没有这个工作?

Am I incorrect here? Has anyone else got this working?

(很长的一天，希望我只是缺少一些简单的东西)

(Been a long day, hopefully I'm just missing something simple)

编辑

在GitHub上询问后，我得到了指向此类的信息: github/aspnet/EntityFramework/blob/dev/src/Microsoft.EntityFrameworkCore/Query/Internal/IAsyncQueryProvider.cs

After asking on GitHub, I got point to this class: github/aspnet/EntityFramework/blob/dev/src/Microsoft.EntityFrameworkCore/Query/Internal/IAsyncQueryProvider.cs

这是到目前为止我尝试实现的目的:

This is what I've gotten to so far in trying to implement this:

using System; using System.Collections.Generic; using System.Linq; using System.Linq.Expressions; using System.Threading; using System.Threading.Tasks; using Microsoft.EntityFrameworkCore.Query.Internal; namespace EFCoreTestQueryProvider { internal class TestAsyncQueryProvider<TEntity>: IAsyncQueryProvider { private readonly IQueryProvider _inner; internal TestAsyncQueryProvider(IQueryProvider inner) { _inner = inner; } IQueryable CreateQuery(Expression expression) { return new TestDbAsyncEnumerable<TEntity>(expression); } IQueryable<TElement> CreateQuery<TElement>(Expression expression) { return new TestDbAsyncEnumerable<TElement>(expression); } object Execute(Expression expression) { return _inner.Execute(expression); } TResult Execute<TResult>(Expression expression) { return _inner.Execute<TResult>(expression); } IAsyncEnumerable<TResult> ExecuteAsync<TResult>(Expression expression) { return Task.FromResult(Execute<TResult>(expression)).ToAsyncEnumerable(); } Task<TResult> IAsyncQueryProvider.ExecuteAsync<TResult>(Expression expression, CancellationToken cancellationToken) { return Task.FromResult(Execute<TResult>(expression)); } } internal class TestDbAsyncEnumerable<T> : EnumerableQuery<T>, System.Collections.Generic.IAsyncEnumerable<T>, IQueryable<T> { public TestDbAsyncEnumerable(IEnumerable<T> enumerable) : base(enumerable) { } public TestDbAsyncEnumerable(Expression expression) : base(expression) { } public IAsyncEnumerator<T> GetAsyncEnumerator() { return new TestDbAsyncEnumerable<T>(this.AsEnumerable()).ToAsyncEnumerable(); } IDbAsyncEnumerator IDbAsyncEnumerable.GetAsyncEnumerator() { return GetAsyncEnumerator(); } IAsyncEnumerator<T> IAsyncEnumerable<T>.GetEnumerator() { throw new NotImplementedException(); } IQueryProvider IQueryable.Provider { get { return new TestAsyncQueryProvider<T>(this); } } } }

我现在试图实现这一点，并遇到了更多的问题，特别是围绕这两种方法:

I've now tried to implement this and have run into some more issues, specifically around these two methods:

public IAsyncEnumerator<T> GetAsyncEnumerator() { return new TestDbAsyncEnumerable<T>(this.AsEnumerable()).ToAsyncEnumerable(); } IDbAsyncEnumerator IDbAsyncEnumerable.GetAsyncEnumerator() { return GetAsyncEnumerator(); }

我希望有人可以指出我在做错事情的正确方向.

I'm hoping that somebody could point me in the right direction as to what I'm doing wrong.

推荐答案

我终于可以使用它了.他们将EntityFrameworkCore中的接口从IDbAsyncEnumerable更改为IAsyncEnumerable，因此以下代码对我有用:

I finally got this to work. They slightly changed the interfaces in EntityFrameworkCore from IDbAsyncEnumerable to IAsyncEnumerable so the following code worked for me:

public class AsyncEnumerable<T> : EnumerableQuery<T>, IAsyncEnumerable<T>, IQueryable<T> { public AsyncEnumerable(Expression expression) : base(expression) { } public IAsyncEnumerator<T> GetEnumerator() => new AsyncEnumerator<T>(this.AsEnumerable().GetEnumerator()); } public class AsyncEnumerator<T> : IAsyncEnumerator<T> { private readonly IEnumerator<T> enumerator; public AsyncEnumerator(IEnumerator<T> enumerator) => this.enumerator = enumerator ?? throw new ArgumentNullException(); public T Current => enumerator.Current; public void Dispose() { } public Task<bool> MoveNext(CancellationToken cancellationToken) => Task.FromResult(enumerator.MoveNext()); } [Fact] public async Task TestEFCore() { var data = new List<Entity>() { new Entity(), new Entity(), new Entity() }.AsQueryable(); var mockDbSet = new Mock<DbSet<Entity>>(); mockDbSet.As<IAsyncEnumerable<Entity>>() .Setup(d => d.GetEnumerator()) .Returns(new AsyncEnumerator<Entity>(data.GetEnumerator())); mockDbSet.As<IQueryable<Entity>>().Setup(m => m.Provider).Returns(data.Provider); mockDbSet.As<IQueryable<Entity>>().Setup(m => m.Expression).Returns(data.Expression); mockDbSet.As<IQueryable<Entity>>().Setup(m => m.ElementType).Returns(data.ElementType); mockDbSet.As<IQueryable<Entity>>().Setup(m => m.GetEnumerator()).Returns(data.GetEnumerator()); var mockCtx = new Mock<SomeDbContext>(); mockCtx.SetupGet(c => c.Entities).Returns(mockDbSet.Object); var entities = await mockCtx.Object.Entities.ToListAsync(); Assert.NotNull(entities); Assert.Equal(3, entities.Count()); }

您也许可以清理AsyncEnumerable和AsyncEnumerator的那些测试实现.我没有尝试，只是让它起作用.

You might be able to clean up those test implementations of the AsyncEnumerable and AsyncEnumerator even more. I didn't try, I just got it to work.

请记住，您需要将DbContext上的DbSet标记为virtual，否则您将需要在DbContext上实现一些接口包装，以使其正常工作.

Remember your DbSet on your DbContext needs to be marked as virtual or else you will need to implement some interface wrapper over the DbContext to make this work properly.