parsertestcase.java

Grammatica is a C# and Java parser generator (compiler compiler). It improves upon simlar tools (lik

/*
 * ParserTestCase.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.test;

import java.io.PrintWriter;
import java.io.StringWriter;

import junit.framework.TestCase;

import net.percederberg.grammatica.parser.Node;
import net.percederberg.grammatica.parser.ParseException;
import net.percederberg.grammatica.parser.Parser;
import net.percederberg.grammatica.parser.ParserCreationException;
import net.percederberg.grammatica.parser.ParserLogException;

/**
 * Base class for all the parser test cases.
 *
 * @author   Per Cederberg, <per at percederberg dot net>
 * @version  1.0
 */
abstract class ParserTestCase extends TestCase {

    /**
     * Creates a new test case.
     * 
     * @param name           the test case name
     */
    public ParserTestCase(String name) {
        super(name);
    }

    /**
     * Parses with the parser and checks the output. If the parsing
     * failed or if the tree didn't match the specified output, a test
     * failure will be reported. 
     * 
     * @param parser         the parser to use
     * @param output         the expected parse tree
     */
    protected void parse(Parser parser, String output) {
        try {
            validateTree(parser.parse(), output);
        } catch (ParserCreationException e) {
            fail(e.getMessage());
        } catch (ParserLogException e) {
            fail(e.getError(0).getMessage());
        }
    }
    
    /**
     * Parses with the parser and checks the parse error. If the 
     * parsing succeeded or if the parse exception didn't match the 
     * specified values, a test failure will be reported. 
     * 
     * @param parser         the parser to use
     * @param type           the parse error type
     * @param line           the line number
     * @param column         the column number
     */
    protected void failParse(Parser parser, 
                             int type, 
                             int line, 
                             int column) {

        try {
            parser.parse();
            fail("parsing succeeded");
        } catch (ParserCreationException e) {
            fail(e.getMessage());
        } catch (ParserLogException e) {
            ParseException  p = e.getError(0);  
            
            assertEquals("error count", 1, e.getErrorCount());
            assertEquals("error type", type, p.getErrorType());
            assertEquals("line number", line, p.getLine());
            assertEquals("column number", column, p.getColumn());
        }
    }

    /**
     * Validates that a parse tree is identical to a string 
     * representation. If the two representations mismatch, a test 
     * failure will be reported.
     * 
     * @param root           the parse tree root node
     * @param str            the string representation
     */
    private void validateTree(Node root, String str) {
        StringWriter output = new StringWriter();
        
        root.printTo(new PrintWriter(output));
        validateLines(str, output.toString());
    }
    
    /**
     * Validates that two strings are identical. If the two strings 
     * mismatch, a test failure will be reported.
     * 
     * @param expected       the expected result
     * @param result         the result obtained
     */
    private void validateLines(String expected, String result) {
        int  line = 1;
        int  pos;

        pos = result.indexOf('\n');
        while (pos > 0) {
            if (expected.length() < pos) {
                break;
            }
            validateLine(line,
                         expected.substring(0, pos), 
                         result.substring(0, pos));
            expected = expected.substring(pos + 1);
            result = result.substring(pos + 1);
            pos = result.indexOf('\n');
            line++;
        }
        validateLine(line, expected, result);
    }
    
    /**
     * Validates that two strings are identical. If the two strings 
     * mismatch, a test failure will be reported.
     *
     * @param line           the line number to report 
     * @param expected       the expected result
     * @param result         the result obtained
     */
    private void validateLine(int line, String expected, String result) {
        if (!expected.equals(result)) {
            fail("on line: " + line + ", expected: '" + expected +
                 "', found: '" + result + "'");
        }
    }
}