ContentDigestTest.java

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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package com.oracle.truffle.api.test.source;

import java.lang.reflect.Method;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.util.Random;

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

import com.oracle.truffle.api.test.ReflectionUtils;

public class ContentDigestTest {
    @Test
    public void emptyMD2() throws Exception {
        assertDigest(new byte[0], "Empty MD2 digest");
    }

    @Test
    public void hiMD2() throws Exception {
        assertDigest("Hi".getBytes("UTF-8"), "Empty MD2 digest");
    }

    @Test
    public void helloWorldMD2() throws Exception {
        assertDigest("Hello World!".getBytes("UTF-8"), "Empty MD2 digest");
    }

    @Test
    public void minusMD2() throws Exception {
        assertDigest(new byte[]{-75, 119}, "MD2 digest for negative byte");
    }

    @Test
    public void computeMD2s() throws Exception {
        for (int i = 0; i < 100; i++) {
            long seed = System.currentTimeMillis();
            final String msg = "Digest for seed " + seed + " is the same";

            Random random = new Random(seed);

            int len = random.nextInt(2048);
            byte[] arr = new byte[len];
            random.nextBytes(arr);

            assertDigest(arr, msg);
        }
    }

    private static void assertDigest(byte[] arr, final String msg) throws Exception {
        byte[] result = MessageDigest.getInstance("MD2").digest(arr);
        String expecting = new BigInteger(1, result).toString(16);

        Method m = Class.forName("com.oracle.truffle.api.source.Content").getDeclaredMethod("digest", byte[].class, int.class, int.class);
        ReflectionUtils.setAccessible(m, true);
        String own = (String) m.invoke(null, arr, 0, arr.length);

        Assert.assertEquals(msg, expecting, own);
    }

}