public void CheckSetIntersectWith()
        {
            q = new SetCollection <int>();
            var testSet1 = new int[] { 1, 2, 3, 4, 5 };

            q.AddRange(testSet1);
            q.IntersectWith(new int[] { 1, 5 });
            var expected = new int[] { 1, 5 };

            CollectionAssert.AreEqual(expected, q);
        }