public void EmptyResultTest()
        {
            var list = new List <string> {
                "a", "abc", "b"
            };
            var outputList = list.FilterBySubStrCombination(3);

            Assert.IsTrue(outputList.Count == 0);
        }
        public void Result1Test()
        {
            var list = new List <string> {
                "ab", "abc", "c", "ffff", "gg"
            };
            var outputList = list.FilterBySubStrCombination(3);

            Assert.IsTrue(outputList.Count == 1);
            Assert.IsTrue(outputList[0] == "abc");
        }