public void IsProperSubsetIsCorrect()
        {
            var set = new MySet <int> {
                1, 3, 0, 2, 4, 7, 9
            };
            var list = new List <int>()
            {
                0, 1, 2, 3, 4, 5, 6, 7, 8, 9
            };

            Assert.IsTrue(set.IsProperSubsetOf(list));
            set.Add(10);
            Assert.IsFalse(set.IsProperSubsetOf(list));
        }
 public void IsProperSubsetOfTrueTest()
 {
     set.Add(1);
     set.Add(3);
     Assert.IsTrue(set.IsProperSubsetOf(list));
 }