"C : 'c';\n");
CharStream input = new ANTLRStringStream("abc");
Interpreter lexEngine = new Interpreter(g, input);
TokenRewriteStream tokens = new TokenRewriteStream(lexEngine);
tokens.LT(1); // fill buffer
tokens.insertBefore(1, "x");
tokens.insertBefore(0, "y");
tokens.insertBefore(1, "z");
String result = tokens.toString();
String expecting = "yazxbc";
assertEquals(expecting, result);