public void GetAllMutations()
        {
            var dictionary = new List<string> { "AA", "BA", "BB" };
            var wordChains = new WordChains(dictionary);

            var allMutations = wordChains.FindAllMutations("BA");

            Assert.AreEqual(2, allMutations.Count);
            Assert.AreEqual(allMutations[0], "AA");
            Assert.AreEqual(allMutations[1], "BB");
        }