testrecursivedescentparser.java

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/*
 * TestRecursiveDescentParser.java
 *
 * This work is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published
 * by the Free Software Foundation; either version 2 of the License,
 * or (at your option) any later version.
 *
 * This work is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 * USA
 *
 * As a special exception, the copyright holders of this library give
 * you permission to link this library with independent modules to
 * produce an executable, regardless of the license terms of these
 * independent modules, and to copy and distribute the resulting
 * executable under terms of your choice, provided that you also meet,
 * for each linked independent module, the terms and conditions of the
 * license of that module. An independent module is a module which is
 * not derived from or based on this library. If you modify this
 * library, you may extend this exception to your version of the
 * library, but you are not obligated to do so. If you do not wish to
 * do so, delete this exception statement from your version.
 *
 * Copyright (c) 2003 Per Cederberg. All rights reserved.
 */

package net.percederberg.grammatica.parser;

import junit.framework.TestCase;

/**
 * A test case for the RecursiveDescentParser class.
 *
 * @author   Per Cederberg, <per at percederberg dot net>
 * @version  1.0
 */
public class TestRecursiveDescentParser extends TestCase {

    /**
     * A token constant.
     */
    private static final int T1 = 1001;

    /**
     * A token constant.
     */
    private static final int T2 = 1002;

    /**
     * A token constant.
     */
    private static final int T3 = 1003;

    /**
     * A production constant.
     */
    private static final int P1 = 2001;

    /**
     * A production constant.
     */
    private static final int P2 = 2002;

    /**
     * A production constant.
     */
    private static final int P3 = 2003;

    /**
     * The production pattern variable used in all tests.
     */
    private ProductionPattern pattern; 

    /**
     * The production pattern alternative variable used in all tests.
     */
    private ProductionPatternAlternative alt;

    /**
     * Tests adding an empty pattern to the parser.
     */
    public void testEmptyPattern() {
        pattern = new ProductionPattern(P1, "P1");
        alt = new ProductionPatternAlternative();
        addAlternative(pattern, alt);
        failAddPattern(createParser(), pattern);
    }
    
    /**
     * Tests adding a possible empty pattern to the parser.
     */
    public void testPossiblyEmptyPattern() {
        pattern = new ProductionPattern(P1, "P1");
        alt = new ProductionPatternAlternative();
        alt.addToken(T1, 1, 1);
        addAlternative(pattern, alt);
        alt = new ProductionPatternAlternative();
        alt.addToken(T2, 0, 1);
        addAlternative(pattern, alt);
        failAddPattern(createParser(), pattern);
    }
    
    /**
     * Tests adding a left-recursive pattern to the parser.
     */
    public void testLeftRecursivePattern() {
        pattern = new ProductionPattern(P1, "P1");
        alt = new ProductionPatternAlternative();
        alt.addProduction(P1, 0, 1);
        alt.addToken(T1, 1, 1);
        addAlternative(pattern, alt);
        failAddPattern(createParser(), pattern);
    }

    /**
     * Tests adding a right-recursive pattern to the parser.
     */
    public void testRightRecursivePattern() {
        pattern = new ProductionPattern(P1, "P1");
        alt = new ProductionPatternAlternative();
        alt.addToken(T1, 1, 1);
        alt.addProduction(P1, 0, 1);
        addAlternative(pattern, alt);
        addPattern(createParser(), pattern);
    }

    /**
     * Tests adding the same pattern twice.
     */
    public void testDuplicatePattern() {
        Parser  parser = createParser();

        pattern = new ProductionPattern(P1, "P1");
        alt = new ProductionPatternAlternative();
        alt.addToken(T1, 1, 1);
        addAlternative(pattern, alt);
        addPattern(parser, pattern);
        failAddPattern(parser, pattern);
    }

    /**
     * Tests adding two patterns with the same id.
     */
    public void testPatternCollision() {
        Parser  parser = createParser();

        pattern = new ProductionPattern(P1, "P1");
        alt = new ProductionPatternAlternative();
        alt.addToken(T1, 1, 1);
        addAlternative(pattern, alt);
        addPattern(parser, pattern);

        pattern = new ProductionPattern(P1, "P2");
        alt = new ProductionPatternAlternative();
        alt.addToken(T2, 1, 1);
        addAlternative(pattern, alt);
        failAddPattern(parser, pattern);
    }

    /**
     * Tests adding two patterns with the same alternatives.
     */
    public void testIdenticalPatterns() {
        Parser  parser = createParser();

        pattern = new ProductionPattern(P1, "P1");
        alt = new ProductionPatternAlternative();
        alt.addToken(T1, 1, 1);
        addAlternative(pattern, alt);
        addPattern(parser, pattern);

        pattern = new ProductionPattern(P2, "P2");
        alt = new ProductionPatternAlternative();
        alt.addToken(T1, 1, 1);
        addAlternative(pattern, alt);
        addPattern(parser, pattern);
    }

    /**
     * Tests a simple grammar loop.
     */
    public void testSimpleGrammarLoop() {
        Parser parser = createParser();

        pattern = new ProductionPattern(P1, "P1");
        alt = new ProductionPatternAlternative();
        alt.addProduction(P2, 1, 1);
        addAlternative(pattern, alt);
        addPattern(parser, pattern);

        pattern = new ProductionPattern(P2, "P2");
        alt = new ProductionPatternAlternative();
        alt.addProduction(P1, 1, 1);
        addAlternative(pattern, alt);
        addPattern(parser, pattern);

        failPrepareParser(parser);
    }

    /**
     * Tests a complex grammar loop with optional parts and 
     * alternatives.
     */
    public void testComplexGrammarLoop() {
        Parser parser = createParser();

        pattern = new ProductionPattern(P1, "P1");
        alt = new ProductionPatternAlternative();
        alt.addProduction(P2, 1, 1);
        addAlternative(pattern, alt);
        addPattern(parser, pattern);

        pattern = new ProductionPattern(P2, "P2");
        alt = new ProductionPatternAlternative();
        alt.addProduction(P3, 0, 1);
        alt.addToken(T1, 1, 1);
        addAlternative(pattern, alt);
        addPattern(parser, pattern);

        pattern = new ProductionPattern(P3, "P3");
        alt = new ProductionPatternAlternative();
        alt.addToken(T3, 1, 1);
        addAlternative(pattern, alt);
        alt = new ProductionPatternAlternative();
        alt.addProduction(P1, 0, 1);
        alt.addToken(T2, 1, 1);
        addAlternative(pattern, alt);
        addPattern(parser, pattern);

        failPrepareParser(parser);
    }
    
    /**
     * Tests an unresolvable conflict between two productions.
     */
    public void testProductionConflict() {
        Parser parser = createParser();

        pattern = new ProductionPattern(P1, "P1");
        alt = new ProductionPatternAlternative();
        alt.addProduction(P2, 1, 1);
        addAlternative(pattern, alt);
        alt = new ProductionPatternAlternative();
        alt.addProduction(P3, 1, 1);
        addAlternative(pattern, alt);
        addPattern(parser, pattern);

        pattern = new ProductionPattern(P2, "P2");
        alt = new ProductionPatternAlternative();
        alt.addToken(T1, 0, -1);
        alt.addToken(T2, 1, 1);
        addAlternative(pattern, alt);
        addPattern(parser, pattern);
        
        pattern = new ProductionPattern(P3, "P3");
        alt = new ProductionPatternAlternative();
        alt.addToken(T1, 1, 1);
        alt.addProduction(P3, 0, 1);
        addAlternative(pattern, alt);
        addPattern(parser, pattern);

        failPrepareParser(parser);
    }

    /**
     * Tests an unresolvable conflict between two production 
     * alternatives.
     */
    public void testAlternativeConflict() {
        Parser parser = createParser();

        pattern = new ProductionPattern(P1, "P1");
        alt = new ProductionPatternAlternative();
        alt.addToken(T1, 0, -1);
        alt.addToken(T2, 1, 1);
        addAlternative(pattern, alt);
        alt = new ProductionPatternAlternative();
        alt.addToken(T1, 1, -1);
        alt.addToken(T3, 1, 1);
        addAlternative(pattern, alt);