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.kafka.timeline;
  
  import org.apache.kafka.common.utils.LogContext;
  
  import org.junit.jupiter.api.Test;
  import org.junit.jupiter.api.Timeout;
  
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.List;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  
  
  @Timeout(value = 40)
  public class SnapshotRegistryTest {
      @Test
      public void testEmptyRegistry() {
          SnapshotRegistry registry = new SnapshotRegistry(new LogContext());
          assertThrows(RuntimeException.class, () -> registry.getSnapshot(0));
          assertIteratorContains(registry.iterator());
      }
  
      private static void assertIteratorContains(Iterator<Snapshot> iter,
                                                 Snapshot... snapshots) {
          List<Snapshot> expected = List.of(snapshots);
          List<Snapshot> actual = new ArrayList<>();
          while (iter.hasNext()) {
              Snapshot snapshot = iter.next();
              actual.add(snapshot);
          }
          assertEquals(expected, actual);
      }
  
      @Test
      public void testCreateSnapshots() {
          SnapshotRegistry registry = new SnapshotRegistry(new LogContext());
          Snapshot snapshot123 = registry.getOrCreateSnapshot(123);
          assertEquals(snapshot123, registry.getSnapshot(123));
          assertThrows(RuntimeException.class, () -> registry.getSnapshot(456));
          assertIteratorContains(registry.iterator(), snapshot123);
          assertEquals("Can't create a new in-memory snapshot at epoch 1 because there is already " +
              "a snapshot with epoch 123. Snapshot epochs are 123", assertThrows(RuntimeException.class,
                  () -> registry.getOrCreateSnapshot(1)).getMessage());
          Snapshot snapshot456 = registry.getOrCreateSnapshot(456);
          assertIteratorContains(registry.iterator(), snapshot123, snapshot456);
      }
  
      @Test
      public void testCreateAndDeleteSnapshots() {
          SnapshotRegistry registry = new SnapshotRegistry(new LogContext());
          Snapshot snapshot123 = registry.getOrCreateSnapshot(123);
          Snapshot snapshot456 = registry.getOrCreateSnapshot(456);
          Snapshot snapshot789 = registry.getOrCreateSnapshot(789);
          registry.deleteSnapshot(snapshot456.epoch());
          assertIteratorContains(registry.iterator(), snapshot123, snapshot789);
      }
  
      @Test
      public void testDeleteSnapshotUpTo() {
          SnapshotRegistry registry = new SnapshotRegistry(new LogContext());
          registry.getOrCreateSnapshot(10);
          registry.getOrCreateSnapshot(12);
          Snapshot snapshot14 = registry.getOrCreateSnapshot(14);
          registry.deleteSnapshotsUpTo(14);
          assertIteratorContains(registry.iterator(), snapshot14);
      }
  
      @Test
      public void testCreateSnapshotOfLatest() {
          SnapshotRegistry registry = new SnapshotRegistry(new LogContext());
          registry.getOrCreateSnapshot(10);
          Snapshot latest = registry.getOrCreateSnapshot(12);
          Snapshot duplicate = registry.getOrCreateSnapshot(12);
  
          assertEquals(latest, duplicate);
      }
  
      @Test
      public void testScrub() {
          SnapshotRegistry registry = new SnapshotRegistry(new LogContext(), 2);
          new TimelineInteger(registry).set(123);
          new TimelineInteger(registry).set(123);
          assertEquals(0, registry.numScrubs());
          new TimelineInteger(registry).set(123);
          assertEquals(1, registry.numScrubs());
          new TimelineInteger(registry).set(123);
          new TimelineInteger(registry).set(123);
          new TimelineInteger(registry).set(123);
          assertEquals(2, registry.numScrubs());
      }
  
      @Test
      public void testReset() {
          SnapshotRegistry registry = new SnapshotRegistry(new LogContext(), 2);
          TimelineInteger integer = new TimelineInteger(registry);
          integer.set(123);
          registry.reset();
          assertEquals(0, integer.get());
          assertEquals(1, registry.numScrubs());
      }
  }
  