public void TestCase4()
        {
            RangeDictionary <string> dataStructure = new RangeDictionary <string>();

            dataStructure.AddRange(1, 3, "A");

            Assert.IsTrue(dataStructure.GetValues(5).SequenceEqual(new List <string>()));
        }
        private void AssertGetValuesMethod(RangeDictionary <string> data, int start, int end, HashSet <string> values)
        {
            for (int i = start; i <= end; i++)
            {
                ISet <string> output = data.GetValues(i);

                Assert.IsTrue(output.Count == values.Count);

                foreach (string v in values)
                {
                    Assert.IsTrue(output.Contains(v));
                }
            }
        }