test/unit/org/apache/cassandra/utils/UUIDTests.java

package org.apache.cassandra.utils;
/*
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
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 * KIND, either express or implied.  See the License for the
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import java.nio.ByteBuffer;
import java.util.UUID;

import org.junit.Test;

import org.apache.cassandra.db.marshal.TimeUUIDType;
import org.apache.cassandra.utils.UUIDGen;


public class UUIDTests
{
    @Test
    public void verifyType1()
    {

        UUID uuid = UUIDGen.getTimeUUID();
        assert uuid.version() == 1;
    }

    @Test
    public void verifyOrdering1()
    {
        UUID one = UUIDGen.getTimeUUID();
        UUID two = UUIDGen.getTimeUUID();
        assert one.timestamp() < two.timestamp();
    }


    @Test
    public void testDecomposeAndRaw()
    {
        UUID a = UUIDGen.getTimeUUID();
        byte[] decomposed = UUIDGen.decompose(a);
        UUID b = UUIDGen.getUUID(ByteBuffer.wrap(decomposed));
        assert a.equals(b);
    }

    @Test
    public void testTimeUUIDType()
    {
        TimeUUIDType comp = TimeUUIDType.instance;
        ByteBuffer first = ByteBuffer.wrap(UUIDGen.getTimeUUIDBytes());
        ByteBuffer second = ByteBuffer.wrap(UUIDGen.getTimeUUIDBytes());
        assert comp.compare(first, second) < 0;
        assert comp.compare(second, first) > 0;
        ByteBuffer sameAsFirst = ByteBuffer.wrap(UUIDGen.decompose(UUIDGen.getUUID(first)));
        assert comp.compare(first, sameAsFirst) == 0;
    }

    @Test
    public void testUUIDTimestamp()
    {
        long now = System.currentTimeMillis();
        UUID uuid = UUIDGen.getTimeUUID();
        long tstamp = UUIDGen.getAdjustedTimestamp(uuid);

        // I'll be damn is the uuid timestamp is more than 10ms after now
        assert now <= tstamp && now >= tstamp - 10 : "now = " + now + ", timestamp = " + tstamp;
    }
}