CollectionAssert.IsNotEmpty must dispose Enumerator

[pil0t]

    protected static bool IsEmpty(IEnumerable enumerable)
    {
      ICollection collection = enumerable as ICollection;
      if (collection != null)
        return collection.Count == 0;
      else
        return !enumerable.GetEnumerator().MoveNext();
    }

enumerable.GetEnumerator() - is not disposed