cassandra-analytics-core/src/test/java/org/apache/cassandra/spark/data/partitioner/TokenPartitionerTests.java

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 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
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 *
 *   http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.cassandra.spark.data.partitioner;

import java.math.BigInteger;
import java.nio.ByteBuffer;
import java.util.Arrays;
import java.util.Map;
import java.util.function.Function;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

import com.google.common.collect.Range;
import org.junit.Test;

import org.apache.cassandra.spark.TestUtils;
import org.apache.cassandra.spark.utils.RandomUtils;

import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
import static org.quicktheories.QuickTheory.qt;
import static org.quicktheories.generators.SourceDSL.arbitrary;

public class TokenPartitionerTests
{
    private static final int NUM_TOKEN_TESTS = 100;

    @Test
    public void testTokenPartitioner()
    {
        qt().forAll(TestUtils.partitioners(),
                    arbitrary().pick(Arrays.asList(1, 3, 6, 12, 104, 208, 416)),
                    arbitrary().pick(Arrays.asList(1, 2, 4, 16, 128, 1024)))
            .checkAssert(this::runTest);
    }

    private void runTest(Partitioner partitioner, int numInstances, int numCores)
    {
        TokenPartitioner tokenPartitioner = new TokenPartitioner(TestUtils.createRing(partitioner, numInstances), 1, numCores);
        assertTrue(tokenPartitioner.numPartitions() > 1);

        // Generate some random tokens and verify they only exist in a single token partition
        Map<BigInteger, Integer> tokens = IntStream.range(0, NUM_TOKEN_TESTS)
                                                         .mapToObj(token -> RandomUtils.randomBigInteger(partitioner))
                                                         .collect(Collectors.toMap(Function.identity(), token -> 0));

        for (int partition = 0; partition < tokenPartitioner.numPartitions(); partition++)
        {
            Range<BigInteger> range = tokenPartitioner.getTokenRange(partition);
            for (BigInteger token : tokens.keySet())
            {
                if (range.contains(token))
                {
                    tokens.put(token, tokens.get(token) + 1);
                    assertTrue(tokenPartitioner.isInPartition(token, ByteBuffer.wrap("not important".getBytes()), partition));
                }
            }
        }

        for (Map.Entry<BigInteger, Integer> entry : tokens.entrySet())
        {
            assertFalse("Token not found in any token partitions: " + entry.getKey(), entry.getValue() < 1);
            assertFalse("Token exists in more than one token partition: " + entry.getKey(), entry.getValue() > 1);
        }
    }
}