c# - 为需要 Func 并返回 IEnumerable 的 protected 虚拟方法设置 Moq 调用

Question

我有以下代码。

public class MyClass
{
    protected virtual IEnumerable<TResult> MyMethod<TResult>(Func<IDataReader, IEnumerable<TResult>> arg)
    {
       ....
    }
} 

如何为此设置 Mock 方法？

我尝试跟随但出现错误。

using Moq;
using Moq.Protected;
namespace Foo
{
    [TestClass]
    public class TestClass
    {
        Mock<MyClass> m_mockObject = null;
        [TestMethod]
        public void MyTest()
        {
            m_mockObject = new Mock<MyClass>();
            AddMethod<Func<IDataReader, IEnumerable<SomeOtherClass>>, IEnumerable<SomeOtherClass>>(this.MyMethod);

        }

        private void AddMethod<TIn, TResult>(Func<TIn, TResult> method)
        {
             m_mockObject.Protected().Setup<TResult>(method.Method.Name, ItExpr.IsAny<TIn>())
                                                    .Returns(method); /* THIS LINE IS THROWING THE EXCEPTION */
        }

        public IEnumerable<TResult> MyMethod<TResult>(Func<IDataReader, IEnumerable<TResult>> arg)
        {
            ....
        }
    }
}

运行代码后，调用 Setup 函数时出现以下错误。

> System.ArgumentException was unhandled by user code  HResult=-2147024809  Message=Expression of type 'System.Object' cannot be used for return type 'System.Collections.Generic.IEnumerable`1[SomeOtherClass]'  Source=System.Core  StackTrace:       at System.Linq.Expressions.Expression.ValidateLambdaArgs(Type delegateType, Expression& body, ReadOnlyCollection`1 parameters)       at System.Linq.Expressions.Expression.Lambda[TDelegate](Expression body, String name, Boolean tailCall, IEnumerable`1 parameters)       at System.Linq.Expressions.Expression.Lambda[TDelegate](Expression body, Boolean tailCall, IEnumerable`1 parameters)       at System.Linq.Expressions.Expression.Lambda[TDelegate](Expression body, ParameterExpression[] parameters)       at Moq.Protected.ProtectedMock`1.Setup[TResult](String methodOrPropertyName, Object[] args)       ....       .....  InnerException: 

Answer 1

不确定您为什么要返回一个方法..但您可以尝试将其更改为:

m_mockObject.Protected().Setup<IEnumerable<TResult>>(method.Method.Name, ItExpr.IsAny<TIn>()).Returns(new List<TResult>());

看看是否可行..