关于 c#:How to mock Nhibernate .ToListAsync() in Unit-test with moq？

How to mock Nhibernate .ToListAsync() in Unit-test with moq?

我正在尝试使用 moq 在 ASP.NET Core MVC 应用程序中创建单元测试。不幸的是，Linq IQueryable 数据集不支持 Nhibernate.ToListAsync() 并抛出 System.NotSupportedException: 'Source Provider must be a INhQueryProvider'。
在这段代码中，我模拟了 INhQueryProvider，但这还不够：

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var entities = new List<RequestRole>
{
new RequestRole()
{
Id = 0,
RequestOperator = new RequestOperator() { Id = 1 }
},
new RequestRole()
{
Id = 1,
RequestOperator = new RequestOperator() { Id = 2 }
}
}
.AsQueryable();

// for ToListAsync Mock INhQueryProvider and set it into IQueryable
var queryableProviderMock = new Mock<INhQueryProvider>();
queryableProviderMock.Setup(x => x.ExecuteAsync<IEnumerable<RequestRole>>(It.IsAny<Expression>(), It.IsAny<CancellationToken>()))
.ReturnsAsync(entities);

var queryableMock = new Mock<IQueryable<RequestRole>>();
queryableMock.Setup(x => x.Provider).Returns(queryableProviderMock.Object);
queryableMock.Setup(x => x.Expression).Returns(entities.Expression);
queryableMock.Setup(x => x.GetEnumerator()).Returns(entities.GetEnumerator());
queryableMock.Setup(x => x.ElementType).Returns(entities.ElementType);

// mock CreateQuery, without this Linq.Where throwing"System.NotSupportedException: 'Source Provider must be a INhQueryProvider'"
queryableProviderMock.As<INhQueryProvider>()
.Setup(x => x.CreateQuery<RequestRole>(It.IsAny<Expression>()))
.Returns(queryableMock.Object);

var session = new Mock<ISession>();
session.Setup(s => s.Query<RequestRole>()).Returns(queryableMock.Object);
var returns = session.Object.Query<RequestRole>();

// check work
var tolistasync = await returns
.Where(x => x.Id != 0)
.ToListAsync();

在这种情况下 Linq.Where 条件不起作用，因为我设置了相同的对象而不是过滤。
似乎我应该正确地模拟 INhQueryProvider.CreateQuery，但是如何模拟呢？

您需要指示 CreateQuery 使用该表达式。正如您所见，仅返回模拟的可查询对象不会做任何事情。此外，CreateQuery 将需要返回一个带有实现 INhQueryProvider 的提供程序的 IQueryable。问题在于 Provider 属性没有设置器，因此您无法在现有的可查询对象上设置它。

我解决类似问题的方法是创建自己的序列，我可以在其中设置提供程序。

从创建实现IQueryable<T>和INhQueryProvider的类开始；为简洁起见，我只实现通过 OP 用例所需的内容。请注意， CreateQuery<T> 返回一个可使用实现 INhQueryProvider:

的提供程序的查询

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public class TestingQueryable< T > : IQueryable< T >
{
private readonly IQueryable< T > _queryable;

public TestingQueryable(IQueryable< T > queryable)
{
_queryable = queryable;
Provider = new TestingQueryProvider< T >(_queryable);
}

public Type ElementType => _queryable.ElementType;

public Expression Expression => _queryable.Expression;

public IQueryProvider Provider { get; }

public IEnumerator< T > GetEnumerator()
{
return _queryable.GetEnumerator();
}

IEnumerator IEnumerable.GetEnumerator()
{
return _queryable.GetEnumerator();
}
}

public class TestingQueryProvider< T > : INhQueryProvider
{
public TestingQueryProvider(IQueryable< T > source)
{
Source = source;
}

public IQueryable< T > Source { get; set; }

public IQueryable CreateQuery(Expression expression)
{
throw new NotImplementedException();
}

public IQueryable<TElement> CreateQuery<TElement>(Expression expression)
{
return new TestingQueryable<TElement>(Source.Provider.CreateQuery<TElement>(expression));
}

public object Execute(Expression expression)
{
throw new NotImplementedException();
}

public TResult Execute<TResult>(Expression expression)
{
return Source.Provider.Execute<TResult>(expression);
}

public Task<TResult> ExecuteAsync<TResult>(Expression expression, CancellationToken cancellationToken)
{
return Task.FromResult(Execute<TResult>(expression));
}

public int ExecuteDml<T1>(QueryMode queryMode, Expression expression)
{
throw new NotImplementedException();
}

public Task<int> ExecuteDmlAsync<T1>(QueryMode queryMode, Expression expression, CancellationToken cancellationToken)
{
throw new NotImplementedException();
}

public IFutureEnumerable<TResult> ExecuteFuture<TResult>(Expression expression)
{
throw new NotImplementedException();
}

public IFutureValue<TResult> ExecuteFutureValue<TResult>(Expression expression)
{
throw new NotImplementedException();
}

public void SetResultTransformerAndAdditionalCriteria(IQuery query, NhLinqExpression nhExpression, IDictionary<string, Tuple<object, IType>> parameters)
{
throw new NotImplementedException();
}
}

更新您的查询提供程序设置以使用您的 IQueryable 实现：

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queryProviderMock
.Setup(x => x.CreateQuery<RequestRole>(It.IsAny<Expression>()))
.Returns((Expression providedExpression) =>
{
return new TestingQueryable<RequestRole>(queryable.Provider.CreateQuery<RequestRole>(providedExpression));
});

运行 .Where(x => x.Id != 0).ToListAsync() 并得到预期的结果：

LINQPad result

工作示例

您可以更进一步，只需设置 ISession 模拟以使用您的 IQueryable 实现，如果您不需要专门模拟它，请取消模拟查询提供程序。如果您知道我的意思，我通常不会模拟模拟返回的内容，因此这符合我的同行评审标准。

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[Test]
public async Task Test2()
{
var requestRoles = new List<RequestRole>();
requestRoles.Add(new RequestRole { Id = 0, RequestOperator = new RequestOperator { Id = 1 } });
requestRoles.Add(new RequestRole { Id = 1, RequestOperator = new RequestOperator { Id = 2 } });

var sessionMock = new Mock<ISession>();
sessionMock.Setup(s => s.Query<RequestRole>()).Returns(new TestingQueryable<RequestRole>(requestRoles.AsQueryable()));
var query = sessionMock.Object.Query<RequestRole>();

var result = await query.Where(x => x.Id != 0).ToListAsync();

Assert.Multiple(() =>
{
Assert.That(result.Count, Is.EqualTo(1));
Assert.That(result.Single(), Is.EqualTo(requestRoles.Last()));
});
}