Anagrams.Bag.test_subtraction C# (CSharp) Method

        private static void test_subtraction(string minuend, string subtrahend, string expected_difference)
        {
            string actual_difference = subtract_strings(minuend, subtrahend);
            System.Diagnostics.Trace.Assert (actual_difference == expected_difference,
                                             "Test failure: "
                                             + "Subtracting `" + subtrahend
                                             + "' from `" + minuend
                                             + "' yielded `" + actual_difference
                                             + "', but should have yielded `" + expected_difference + "'.");
        }