CollectionAssert泛型使用？ [英] CollectionAssert use with generics?

问题描述

看来， Col​​lectionAssert 不能与仿制药使用。这是超级沮丧;在code我想测试并使用泛型。我该怎么办？编写样板在两者之间转换？手动检查集合等价？

It appears that CollectionAssert cannot be used with generics. This is super frustrating; the code I want to test does use generics. What am I to do? Write boilerplate to convert between the two? Manually check collection equivalence?

这将失败：

ICollection<IDictionary<string, string>> expected = // ...

IEnumerable<IDictionary<string, string>> actual = // ...

// error 1 and 2 here
CollectionAssert.AreEqual(expected.GetEnumerator().ToList(), actual.ToList());

// error 3 here
Assert.IsTrue(expected.GetEnumerator().SequenceEquals(actual));

编译器错误：

Compiler errors:

错误1：

System.Collections.Generic.IEnumerator>'不包含'了ToList'，没有扩展方法'了ToList接受第一类型的参数'System.Collections.Generic.IEnumerator>的定义可以发现

'System.Collections.Generic.IEnumerator>' does not contain a definition for 'ToList' and no extension method 'ToList' accepting a first argument of type 'System.Collections.Generic.IEnumerator>' could be found

错误2

System.Collections.Generic.IEnumerator>'不包含'了ToList'，没有扩展方法'了ToList接受第一类型的参数'System.Collections.Generic.IEnumerator>的定义可以发现

'System.Collections.Generic.IEnumerator>' does not contain a definition for 'ToList' and no extension method 'ToList' accepting a first argument of type 'System.Collections.Generic.IEnumerator>' could be found

错误3

System.Collections.Generic.IEnumerator>不包含对SequenceEquals的和定义没有扩展方法'SequenceEquals的接受第一类型的参数'System.Collections.Generic.IEnumerator>可以找到

'System.Collections.Generic.IEnumerator>' does not contain a definition for 'SequenceEquals' and no extension method 'SequenceEquals' accepting a first argument of type 'System.Collections.Generic.IEnumerator>' could be found

我是什么做错了吗？难道我不使用扩展是否正确？

What am I doing wrong? Am I not using extensions correctly?

更新：确定，这看起来有点好转，但仍然无法正常工作：

Update: Ok, this looks a bit better, but still doesn't work:

IEnumerable<IDictionary<string, string>> expected = // ...

IEnumerable<IDictionary<string, string>> actual = // ...

CollectionAssert.AreEquivalent(expected.ToList(), actual.ToList()); // fails
CollectionAssert.IsSubsetOf(expected.ToList(), actual.ToList()); // fails

我不希望比较列表;我只在乎组成员的平等。成员的顺序并不重要。我怎样才能解决这个？

I don't want to be comparing lists; I only care about set membership equality. The order of the members is unimportant. How can I get around this?

推荐答案

您可以使用CollectionAssert与泛型集合。关键是要明白，CollectionAssert方法对的ICollection 运行，尽管一些一般的集合接口落实的ICollection ，名单，其中，T＆GT; 确实

You can use CollectionAssert with generic collections. The trick is to understand that the CollectionAssert methods operate on ICollection, and although few generic collection interfaces implement ICollection, List<T> does.

因此​​，您可以使用了ToList 扩展方法绕过这个限制：

Thus, you can get around this limitation by using the ToList extension method:

IEnumerable<Foo> expected = //...
IEnumerable<Foo> actual = //...
CollectionAssert.AreEqual(expected.ToList(), actual.ToList());

不过，我仍然认为CollectionAssert打破了很多其他的方式，所以我倾向于使用Assert.IsTrue与LINQ扩展方法，像这样的：

That said, I still consider CollectionAssert broken in a lot of other ways, so I tend to use Assert.IsTrue with the LINQ extension methods, like this:

Assert.IsTrue(expected.SequenceEquals(actual));

---

FWIW，我目前使用这些扩展方法来执行其他比较：

---

FWIW, I'm currently using these extension methods to perform other comparisons:

public static class EnumerableExtension
{
    public static bool IsEquivalentTo(this IEnumerable first, IEnumerable second)
    {
        var secondList = second.Cast<object>().ToList();
        foreach (var item in first)
        {
            var index = secondList.FindIndex(item.Equals);
            if (index < 0)
            {
                return false;
            }
            secondList.RemoveAt(index);
        }
        return secondList.Count == 0;
    }

    public static bool IsSubsetOf(this IEnumerable first, IEnumerable second)
    {
        var secondList = second.Cast<object>().ToList();
        foreach (var item in first)
        {
            var index = secondList.FindIndex(item.Equals);
            if (index < 0)
            {
                return false;
            }
            secondList.RemoveAt(index);
        }
        return true;
    }
}

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