package tests;

import AST.*;
import java.io.*;
import junit.framework.TestCase;
import beaver.*;

public class ScannerTests extends TestCase {

  public void testValidKeywords() {
    assertScannerOk("class extends while");
  }
  public void testValidSeparators() {
    assertScannerOk("{} () ; .");
  }
  public void testValidOperators() {
    assertScannerOk("=");
  }
  public void testValidLiterals() {
    assertScannerOk("true false null");
  }
  public void testValidIdentifiers() {
    assertScannerOk("a ab a1 a1b a1b1");
  }
  public void testValidComments() {
    assertScannerOk("// !@#$%^&*abc");
  }
  
  public void testInvalidTokens() {
    assertScannerError("@");
    assertScannerError("!");
    assertScannerError("$");
    assertScannerError("\\");
    assertScannerError("#");
    assertScannerError("<");
    assertScannerError(">");
    assertScannerError("_a");
    assertScannerError("1");
    assertScannerError("1a");
    assertScannerError("// !@#$%^&*abc \n !");
    assertScannerError("/* abc */");
  }


  
  // utilitity asserts to test scanner
  
  protected static void assertScannerOk(String s) {
    try {
      scan(s);
    } catch (Throwable t) {
      fail(t.getMessage());
    }
  }
  
  protected static void assertScannerError(String s) {
    try {
      scan(s);
    } catch (Throwable t) {
      return;
    }
    fail("Expected to find parse error in " + s);
  }
  
  protected static void scan(String s) throws Throwable {
    Reader reader = new StringReader(s);
    PicoJavaScanner scanner = new PicoJavaScanner(new BufferedReader(reader));
    Symbol symbol;
    do {
      symbol = scanner.nextToken();
    } while (symbol.getId() != PicoJavaParser.Terminals.EOF);
    reader.close();
  }
}