MSTest: CollectionAssert.AreEquivalent failed. The expected collection contains 1 occurrence(s) of

Question

Question:

Can anyone tell me why my unit test is failing with this error message?

CollectionAssert.AreEquivalent failed. The

Answer 1

It works if I add an IEqualityComparer as described on MSDN and if I use Enumerable.SequenceEqual. Note however, that now the order of the elements is relevant.

In the unit test

//CollectionAssert.AreEquivalent(list1, list2); // Does not work
Assert.IsTrue(list1.SequenceEqual(list2, new MyPersonEqualityComparer())); // Works

IEqualityComparer

public class MyPersonEqualityComparer : IEqualityComparer
{
    public bool Equals(MyPerson x, MyPerson y)
    {
        if (object.ReferenceEquals(x, y)) return true;

        if (object.ReferenceEquals(x, null) || object.ReferenceEquals(y, null)) return false;

        return x.Name == y.Name && x.Age == y.Age;
    }

    public int GetHashCode(MyPerson obj)
    {
        if (object.ReferenceEquals(obj, null)) return 0;

        int hashCodeName = obj.Name == null ? 0 : obj.Name.GetHashCode();
        int hasCodeAge = obj.Age.GetHashCode();

        return hashCodeName ^ hasCodeAge;
    }
}