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c# - Moq It.IsAnyType 不适用于具有泛型类型的 Func 返回任务

转载 作者:行者123 更新时间:2023-12-04 09:28:08 28 4
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我尝试了 3 种不同的方法来为通用接口(interface)方法设置模拟。只有一种方法有效,但它使用的是显式类型,因此不能通用。我尝试使用 It.IsAnyType,但它似乎与所进行的调用不匹配。
这是示例代码(我希望测试用例 1 返回“asdf”)。我怎样才能让模拟适用于任何类型(不仅仅是字符串?)?

using Moq;
using System;
using System.Threading.Tasks;

namespace blah
{
public class Junk : IGetOrAddable
{
public static void Main()
{
Test(1);
Test(2);
Test(3);
/*********OUTPUT*********
For test case 1, value is null
For test case 2, value is asdf
Unhandled exception. System.ArgumentException: Object of type
'System.Func`2[System.Object,System.Threading.Tasks.Task`1[System.String]]'
cannot be converted to type
'System.Func`2[System.Object,System.Threading.Tasks.Task`1[Moq.It+IsAnyType]]'.
*************************/
}

public static void Test(int testCase)
{
Mock<IGetOrAddable> mock = new Mock<IGetOrAddable>();

//setup the mock to always call the valueFactory function (ignore cache)
switch(testCase)
{
case 1:
{
//use the It.IsAnyType to match any generic invocation of this method
mock.Setup(x => x.GetOrAdd<It.IsAnyType>(It.IsAny<object>(), It.IsAny<Func<object, Task<It.IsAnyType>>>()))
.Returns((object k, Func<object, Task<It.IsAnyType>> f) => f(k));
break;
}
case 2:
{
//use an exact type (string?) to match a specific type invocation of this method
mock.Setup(x => x.GetOrAdd<string?>(It.IsAny<object>(), It.IsAny<Func<object, Task<string?>>>()))
.Returns((object k, Func<object, Task<string?>> f) => f(k));
break;
}
case 3:
{
//try casting It.IsAny<object> per this suggestion: https://stackoverflow.com/a/61322568/352349
mock.Setup(x => x.GetOrAdd<It.IsAnyType>(It.IsAny<object>(), (Func<object, Task<It.IsAnyType>>)It.IsAny<object>()))
.Returns((object k, Func<object, Task<It.IsAnyType>> f) => f(k));
break;
}
}

var value = mock.Object.GetOrAdd<string?>(new object(), RetrieveCoolValue).Result;
Console.WriteLine($"For test case {testCase}, value is {value ?? "null"}");
}
public Task<T> GetOrAdd<T>(object key, Func<object, Task<T>> valueFactory)
{
//complicated cache retrieval stuff here of the sort described in https://docs.microsoft.com/en-us/dotnet/api/system.collections.concurrent.concurrentdictionary-2.getoradd?view=netcore-3.1
throw new NotImplementedException();
}
public static Task<string?> RetrieveCoolValue(object key)
{
return Task.FromResult<string?>("asdf");
}
}

public interface IGetOrAddable
{
Task<T> GetOrAdd<T>(object key, Func<object, Task<T>> valueFactory);
}
}

最佳答案

好吧,直到那个 github 问题得到解决(或出现更好的答案),我遵循 rgvlee 的建议并使用 rgvlee 的一些代码通过 DefaultValueProvider 设置模拟。这是最终代码的样子:

using Moq;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Threading.Tasks;

namespace blah
{
/// <summary>
/// A default value provider for Mocks, lets you specify the value to return in a func.
/// </summary>
public class SomeGenericDefaultValueProvider : DefaultValueProvider
{
private readonly Func<Type, Mock, MethodInfo, IReadOnlyList<object>, object> _f;
public SomeGenericDefaultValueProvider(Func<Type, Mock, MethodInfo, IReadOnlyList<object>, object> f)
{
_f = f;
}

protected override object GetDefaultValue(Type type, Mock mock)
{
var lastInvocation = mock.Invocations.Last();
var methodInfo = lastInvocation.Method;
var args = lastInvocation.Arguments;

try
{
return _f(type, mock, methodInfo, args);
}
catch(NotImplementedException)
{
//just return default for that type
if (type.IsValueType)
{
return Activator.CreateInstance(type);
}
return null;
}
}
}

public class Junk : IGetOrAddable
{
public static void Main()
{
Mock<IGetOrAddable> mock = new Mock<IGetOrAddable>();

//setup the mock to always call the valueFactory function (ignore cache)
mock.DefaultValueProvider = new SomeGenericDefaultValueProvider((type, mock, methodInfo, args) =>
{
if (methodInfo.Name == "GetOrAdd")
{
object key = args[0];
dynamic valueFactory = args[1];
return valueFactory(key);
}
throw new NotImplementedException(); //else throw this so we can let regular behavior occur
});

var value = mock.Object.GetOrAdd<string?>(new object(), RetrieveCoolValue).Result;
Console.WriteLine($"For test, value is {value ?? "null"}");
}
public Task<T> GetOrAdd<T>(object key, Func<object, Task<T>> valueFactory)
{
//complicated cache retrieval stuff here of the sort described in https://docs.microsoft.com/en-us/dotnet/api/system.collections.concurrent.concurrentdictionary-2.getoradd?view=netcore-3.1
throw new NotImplementedException();
}
public static Task<string?> RetrieveCoolValue(object key)
{
return Task.FromResult<string?>("asdf");
}
}

public interface IGetOrAddable
{
Task<T> GetOrAdd<T>(object key, Func<object, Task<T>> valueFactory);
}
}

关于c# - Moq It.IsAnyType 不适用于具有泛型类型的 Func 返回任务,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/62940053/

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