public void Test_Same_Let() { //arrange string word1_test = "JOHRTAD"; string word2_test = "RFGO"; List <int> test_1 = new List <int>() { 1, 3 }; List <int> test_2 = new List <int>() { 3, 0 }; List <List <int> > expect_result = new List <List <int> >(); expect_result.Add(test_1); expect_result.Add(test_2); //act NewFile nf = new NewFile(); List <List <int> > act_result = nf.same_letter(word1_test, word2_test); //assert for (int i = 0; i < act_result.Count; i++) { Assert.AreEqual(expect_result[i][0], act_result[i][0], "Same letter index for word 1 is wrong"); Assert.AreEqual(expect_result[i][1], act_result[i][1], "Same letter index for word 2 is wrong"); } }