core/src/test/java/org/apache/iceberg/TestOffsetsBasedSplitScanTaskIterator.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
 * 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,
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package org.apache.iceberg;

import java.util.List;
import org.apache.iceberg.relocated.com.google.common.collect.Lists;
import org.junit.Assert;
import org.junit.Test;

public class TestOffsetsBasedSplitScanTaskIterator {
  @Test
  public void testSplits() {
    // case when the last row group has more than one byte
    verify(asList(4L, 10L, 15L, 18L, 30L, 45L), 48L, 20, asList(
        asList(4L, 14L), asList(18L, 12L), asList(30L, 18L)));

    // case when the last row group has 1 byte
    verify(asList(4L, 10L, 15L, 18L, 30L, 45L), 46L, 20, asList(
        asList(4L, 14L), asList(18L, 12L), asList(30L, 16L)));

    // case when every row group is of target split size
    verify(asList(4L, 24L, 44L, 64L, 84L, 104L), 124L, 20, asList(
        asList(4L, 20L), asList(24L, 20L), asList(44L, 20L),
        asList(64L, 20L), asList(84L, 20L), asList(104L, 20L)));

    // case when every row group except last one is of target split size
    verify(asList(4L, 24L, 44L, 64L, 84L, 104L), 108L, 20, asList(
        asList(4L, 20L), asList(24L, 20L), asList(44L, 20L),
        asList(64L, 20L), asList(84L, 20L), asList(104L, 4L)));

    // case when target split size is smaller than splits determined by offset boundaries
    verify(asList(4L, 24L, 44L, 64L, 84L, 104L), 108L, 2, asList(
        asList(4L, 20L), asList(24L, 20L), asList(44L, 20L),
        asList(64L, 20L), asList(84L, 20L), asList(104L, 4L)));
  }

  private static void verify(List<Long> offsetRanges, long fileLen,
                             long targetSplitSize, List<List<Long>> offsetLenPairs) {
    List<FileScanTask> tasks = Lists.newArrayList(
        new BaseFileScanTask.OffsetsAwareTargetSplitSizeScanTaskIterator(
            offsetRanges, new MockFileScanTask(fileLen), targetSplitSize));
    Assert.assertEquals("Number of tasks don't match", offsetLenPairs.size(), tasks.size());
    for (int i = 0; i < tasks.size(); i++) {
      FileScanTask task = tasks.get(i);
      List<Long> split = offsetLenPairs.get(i);
      long offset = split.get(0);
      long length = split.get(1);
      Assert.assertEquals(offset, task.start());
      Assert.assertEquals(length, task.length());
    }
  }

  private static <T> List<T> asList(T... items) {
    return Lists.newArrayList(items);
  }
}