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.raft;
  
  import org.apache.kafka.common.Uuid;
  import org.apache.kafka.raft.internals.EpochElection;
  
  import org.junit.jupiter.api.Test;
  
  import java.util.Set;
  import java.util.concurrent.ThreadLocalRandom;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertFalse;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  
  public class EpochElectionTest {
      private final int voter1 = randomReplicaId();
      private final Set<ReplicaKey> voters = Set.of(
          ReplicaKey.of(voter1, Uuid.randomUuid()),
          ReplicaKey.of(voter1 + 1, Uuid.randomUuid()),
          ReplicaKey.of(voter1 + 2, Uuid.randomUuid())
      );
      @Test
      public void testStateOnInitialization() {
          EpochElection epochElection = new EpochElection(voters);
  
          assertEquals(voters, epochElection.unrecordedVoters());
          assertTrue(epochElection.grantingVoters().isEmpty());
          assertTrue(epochElection.rejectingVoters().isEmpty());
          assertFalse(epochElection.isVoteGranted());
          assertFalse(epochElection.isVoteRejected());
          assertFalse(epochElection.isGrantedVoter(voter1));
          assertFalse(epochElection.isRejectedVoter(voter1));
      }
  
      @Test
      public void testRecordGrantedVote() {
          EpochElection epochElection = new EpochElection(voters);
  
          assertTrue(epochElection.recordVote(voter1, true));
          assertEquals(1, epochElection.grantingVoters().size());
          assertTrue(epochElection.grantingVoters().contains(voter1));
          assertEquals(0, epochElection.rejectingVoters().size());
          assertEquals(2, epochElection.unrecordedVoters().size());
          assertTrue(epochElection.isGrantedVoter(voter1));
          assertFalse(epochElection.isRejectedVoter(voter1));
          assertFalse(epochElection.isVoteGranted());
          assertFalse(epochElection.isVoteRejected());
  
          // recording same id as granted
          assertFalse(epochElection.recordVote(voter1, true));
          assertTrue(epochElection.isGrantedVoter(voter1));
          assertFalse(epochElection.isVoteGranted());
  
          // recording majority as granted
          assertTrue(epochElection.recordVote(voter1 + 1, true));
          assertEquals(2, epochElection.grantingVoters().size());
          assertEquals(0, epochElection.rejectingVoters().size());
          assertEquals(1, epochElection.unrecordedVoters().size());
          assertTrue(epochElection.isGrantedVoter(voter1 + 1));
          assertFalse(epochElection.isRejectedVoter(voter1 + 1));
          assertTrue(epochElection.isVoteGranted());
          assertFalse(epochElection.isVoteRejected());
      }
  
      @Test
      public void testRecordRejectedVote() {
          EpochElection epochElection = new EpochElection(voters);
  
          assertTrue(epochElection.recordVote(voter1, false));
          assertEquals(0, epochElection.grantingVoters().size());
          assertEquals(1, epochElection.rejectingVoters().size());
          assertTrue(epochElection.rejectingVoters().contains(voter1));
          assertEquals(2, epochElection.unrecordedVoters().size());
          assertFalse(epochElection.isGrantedVoter(voter1));
          assertTrue(epochElection.isRejectedVoter(voter1));
          assertFalse(epochElection.isVoteGranted());
          assertFalse(epochElection.isVoteRejected());
  
          // recording same id as rejected
          assertFalse(epochElection.recordVote(voter1, false));
          assertFalse(epochElection.isGrantedVoter(voter1));
          assertFalse(epochElection.isVoteRejected());
  
          // recording majority as rejected
          assertTrue(epochElection.recordVote(voter1 + 1, false));
          assertEquals(0, epochElection.grantingVoters().size());
          assertEquals(2, epochElection.rejectingVoters().size());
          assertEquals(1, epochElection.unrecordedVoters().size());
          assertFalse(epochElection.isGrantedVoter(voter1 + 1));
          assertTrue(epochElection.isRejectedVoter(voter1 + 1));
          assertFalse(epochElection.isVoteGranted());
          assertTrue(epochElection.isVoteRejected());
      }
  
      @Test
      public void testOverWritingVote() {
          EpochElection epochElection = new EpochElection(voters);
  
          assertTrue(epochElection.recordVote(voter1, true));
          assertFalse(epochElection.recordVote(voter1, false));
          assertEquals(0, epochElection.grantingVoters().size());
          assertEquals(1, epochElection.rejectingVoters().size());
          assertTrue(epochElection.rejectingVoters().contains(voter1));
          assertFalse(epochElection.isGrantedVoter(voter1));
          assertTrue(epochElection.isRejectedVoter(voter1));
          assertFalse(epochElection.isVoteGranted());
          assertFalse(epochElection.isVoteRejected());
  
          assertTrue(epochElection.recordVote(voter1 + 2, false));
          assertFalse(epochElection.recordVote(voter1 + 2, true));
          assertEquals(1, epochElection.grantingVoters().size());
          assertEquals(1, epochElection.rejectingVoters().size());
          assertTrue(epochElection.grantingVoters().contains(voter1 + 2));
          assertTrue(epochElection.isGrantedVoter(voter1 + 2));
          assertFalse(epochElection.isRejectedVoter(voter1 + 2));
          assertFalse(epochElection.isVoteGranted());
          assertFalse(epochElection.isVoteRejected());
      }
  
      private static int randomReplicaId() {
          return ThreadLocalRandom.current().nextInt(1025);
      }
  }
  