Here is a reimplementation of CollectionAssert.AreEquivalent (reference code was decompiled with DotPeek) however instead of throwing a exception it returns a bool.
public class CollectionMethods
{
public static bool AreEquivalent(ICollection expected, ICollection actual)
{
//We can do a few quick tests we can do to get a easy true or easy false.
//Is one collection null and one not?
if (Object.ReferenceEquals(expected, null) != Object.ReferenceEquals(actual, null))
return false;
//Do they both point at the same object?
if (Object.ReferenceEquals(expected, actual))
return true;
//Do they have diffrent counts?
if (expected.Count != actual.Count)
return false;
//Do we have two empty collections?
if (expected.Count == 0)
return true;
//Ran out of easy tests, now have to do the slow work.
int nullCount1;
Dictionary elementCounts1 = CollectionMethods.GetElementCounts(expected, out nullCount1);
int nullCount2;
Dictionary elementCounts2 = CollectionMethods.GetElementCounts(actual, out nullCount2);
//One last quick check, do the two collections have the same number of null elements?
if (nullCount2 != nullCount1)
{
return false;
}
//Check for each element and see if we see them the same number of times in both collections.
foreach (KeyValuePair kvp in elementCounts1)
{
int expectedCount = kvp.Value;
int actualCount;
elementCounts2.TryGetValue(key, out actualCount);
if (expectedCount != actualCount)
{
return false;
}
}
return true;
}
private static Dictionary GetElementCounts(ICollection collection, out int nullCount)
{
Dictionary dictionary = new Dictionary();
nullCount = 0;
foreach (object key in (IEnumerable)collection)
{
if (key == null)
{
++nullCount;
}
else
{
int num;
dictionary.TryGetValue(key, out num);
++num;
dictionary[key] = num;
}
}
return dictionary;
}
}
