ChangeMonitorInputStreamTest.java

/*
 * This file is part of the OWASP Proxy, a free intercepting proxy library.
 * Copyright (C) 2008-2010 Rogan Dawes <rogan@dawes.za.net>
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to:
 * The Free Software Foundation, Inc., 
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

package org.owasp.proxy.io;

import java.io.ByteArrayInputStream;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;

import org.junit.Assert;
import org.junit.BeforeClass;
import org.junit.Test;

public class ChangeMonitorInputStreamTest {

    private static byte[] original;

    @BeforeClass
    public static void setUpBeforeClass() throws Exception {
        original = new byte[16384];
        for (int i = 0; i < original.length; i++) {
            original[i] = (byte) (i % 256);
        }
    }

    @Test
    public void testBasicCopy() throws Exception {
        InputStream in = new ByteArrayInputStream(original);
        ChangeMonitorInputStream cmis = new ChangeMonitorInputStream(in);
        in = cmis;
        int read = flush(in);
        Assert.assertEquals("Read the wrong number of bytes", original.length,
                read);
        compare(original, cmis.getOriginal());
    }

    @Test
    public void testSimpleWatch() throws Exception {
        InputStream in = new ByteArrayInputStream(original);
        ChangeMonitorInputStream cmis = new ChangeMonitorInputStream(in);
        in = cmis.watch(cmis, "No changes");
        int read = flush(in);
        Assert.assertEquals("Read the wrong number of bytes", original.length,
                read);
        compare(original, cmis.getOriginal());
        Assert.assertEquals("Unexpectd copy!", 0,
                cmis.getModifiedStreams().length);
    }

    @Test
    public void testChangingWatch() throws Exception {
        InputStream in = new ByteArrayInputStream(original);
        ChangeMonitorInputStream cmis = new ChangeMonitorInputStream(in);
        in = cmis;
        in = new ModuloInputStream(in, 16);
        in = cmis.watch(in, "Modulo 16");
        int read = flush(in);
        Assert.assertEquals("Read the wrong number of bytes", original.length,
                read);
        Assert.assertEquals("missing copy!", 1,
                cmis.getModifiedStreams().length);
        byte[] copy = cmis.getModifiedStreams()[0].toByteArray();
        for (int i = 0; i < original.length; i++)
            Assert.assertEquals("Incorrect modulo at " + i,
                    (byte) ((original[i] % 16) & 0xFF), copy[i]);
    }

    private int flush(InputStream in) throws IOException {
        byte[] buff = new byte[767];
        int read = 0, got;
        // while (in.read() > -1)
        // read++;
        while ((got = in.read(buff)) > 0) {
            read += got;
            // for (int i = 0; i < 16; i++) {
            // if (in.read() > -1) {
            // read++;
            // } else {
            // break;
            // }
            // }
        }
        return read;
    }

    private void compare(byte[] src, byte[] dst) {
        Assert.assertEquals("lengths differ", src.length, dst.length);
        for (int i = 0; i < src.length; i++)
            Assert.assertEquals("Difference at " + i, src[i], dst[i]);
    }

    private static class ModuloInputStream extends FilterInputStream {
        private int modulo;

        public ModuloInputStream(InputStream in, int modulo) {
            super(in);
            this.modulo = modulo;
        }

        public int read() throws IOException {
            int ret = super.read();
            if (ret > 0)
                ret = (ret % modulo) & 0xFF;
            return ret;
        }

        public int read(byte[] b, int off, int len) throws IOException {
            int ret = super.read(b, off, len);
            if (ret > 0) {
                for (int i = off; i < off + len; i++)
                    b[i] = (byte) (b[i] % modulo);
            }
            return ret;
        }
    }
}