public static void TestTokenFactory(string code, params SyntaxKeyword[] types)
        {
            SyntaxKeyword[] generatedtypes = new TokenFactory(new SourceCode(code)).Select(n => n.Kind).ToArray();
            Assert.AreEqual(types.Length, generatedtypes.Count());

            for (int i = 0; i < types.Length; i++)
            {
                SyntaxKeyword left  = generatedtypes.ElementAt(i);
                SyntaxKeyword right = types[i];

                Assert.AreEqual(left, right);
            }
        }