content: /*
   * 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 "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.beam.sdk.extensions.sorter;
  
  import static org.hamcrest.MatcherAssert.assertThat;
  import static org.hamcrest.Matchers.contains;
  import static org.hamcrest.Matchers.emptyIterable;
  import static org.hamcrest.Matchers.is;
  import static org.junit.Assert.assertTrue;
  
  import java.util.Random;
  import org.apache.beam.sdk.values.KV;
  import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.primitives.UnsignedBytes;
  import org.junit.rules.ExpectedException;
  
  /** A set of basic tests for {@link Sorter}s. */
  @SuppressWarnings({
    "rawtypes" // TODO(https://github.com/apache/beam/issues/20447)
  })
  class SorterTestUtils {
  
    public static void testEmpty(Sorter sorter) throws Exception {
      assertThat(sorter.sort(), is(emptyIterable()));
    }
  
    @SuppressWarnings("unchecked")
    public static void testSingleElement(Sorter sorter) throws Exception {
      KV<byte[], byte[]> kv = KV.of(new byte[] {4, 7}, new byte[] {1, 2});
      sorter.add(kv);
      assertThat(sorter.sort(), contains(kv));
    }
  
    @SuppressWarnings("unchecked")
    public static void testEmptyKeyValueElement(Sorter sorter) throws Exception {
      KV<byte[], byte[]> kv = KV.of(new byte[] {}, new byte[] {});
      sorter.add(kv);
      assertThat(sorter.sort(), contains(kv));
    }
  
    @SuppressWarnings("unchecked")
    public static void testMultipleIterations(Sorter sorter) throws Exception {
      KV<byte[], byte[]>[] kvs =
          new KV[] {
            KV.of(new byte[] {0}, new byte[] {}),
            KV.of(new byte[] {0, 1}, new byte[] {}),
            KV.of(new byte[] {1}, new byte[] {})
          };
      sorter.add(kvs[1]);
      sorter.add(kvs[2]);
      sorter.add(kvs[0]);
      Iterable<KV<byte[], byte[]>> sorted = sorter.sort();
      assertThat(sorted, contains(kvs[0], kvs[1], kvs[2]));
      // Iterate second time.
      assertThat(sorted, contains(kvs[0], kvs[1], kvs[2]));
    }
  
    /** Class that generates a new sorter. Used when performance testing multiple sorter creation. */
    interface SorterGenerator {
      Sorter generateSorter();
    }
  
    /**
     * Generates random records and executes a test with the provided number of sorters and number of
     * records per sorter.
     */
    public static void testRandom(
        SorterGenerator sorterGenerator, int numSorters, int numRecordsPerSorter) throws Exception {
      long start = System.currentTimeMillis();
      for (int i = 0; i < numSorters; ++i) {
        Sorter sorter = sorterGenerator.generateSorter();
        Random rnd = new Random(0L);
        for (int j = 0; j < numRecordsPerSorter; ++j) {
          byte[] key = new byte[8];
          byte[] value = new byte[8];
          rnd.nextBytes(key);
          rnd.nextBytes(value);
          sorter.add(KV.of(key, value));
        }
  
        byte[] prevKey = null;
        for (KV<byte[], byte[]> record : sorter.sort()) {
          assertTrue(
              prevKey == null
                  || UnsignedBytes.lexicographicalComparator().compare(prevKey, record.getKey()) < 0);
          prevKey = record.getKey();
        }
      }
      long end = System.currentTimeMillis();
      System.out.println(
          "Took "
              + (end - start)
              + "ms for "
              + numRecordsPerSorter * numSorters * 1000.0 / (end - start)
              + " records/s");
    }
  
    /** Tests trying to call add after calling sort. Should throw an exception. */
    public static void testAddAfterSort(Sorter sorter, ExpectedException thrown) throws Exception {
      thrown.expect(IllegalStateException.class);
      thrown.expectMessage(is("Records can only be added before sort()"));
      KV<byte[], byte[]> kv = KV.of(new byte[] {4, 7}, new byte[] {1, 2});
      sorter.add(kv);
      sorter.sort();
      sorter.add(kv);
    }
  
    /** Tests trying to calling sort twice. Should throw an exception. */
    public static void testSortTwice(Sorter sorter, ExpectedException thrown) throws Exception {
      thrown.expect(IllegalStateException.class);
      thrown.expectMessage(is("sort() can only be called once."));
      KV<byte[], byte[]> kv = KV.of(new byte[] {4, 7}, new byte[] {1, 2});
      sorter.add(kv);
      sorter.sort();
      sorter.sort();
    }
  }
  