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   * 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.clients.consumer;
  
  
  import org.apache.kafka.common.Cluster;
  import org.apache.kafka.common.Configurable;
  import org.apache.kafka.common.KafkaException;
  import org.apache.kafka.common.serialization.StringDeserializer;
  
  import org.junit.jupiter.api.Test;
  
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.List;
  import java.util.Map;
  import java.util.Properties;
  
  import static org.apache.kafka.clients.consumer.ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG;
  import static org.apache.kafka.clients.consumer.ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG;
  import static org.apache.kafka.clients.consumer.ConsumerPartitionAssignor.getAssignorInstances;
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertInstanceOf;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  
  public class ConsumerPartitionAssignorTest {
  
      @Test
      public void shouldInstantiateAssignor() {
          List<ConsumerPartitionAssignor> assignors = getAssignorInstances(
                  Collections.singletonList(StickyAssignor.class.getName()),
                  Collections.emptyMap()
          );
          assertInstanceOf(StickyAssignor.class, assignors.get(0));
      }
  
      @Test
      public void shouldInstantiateListOfAssignors() {
          List<ConsumerPartitionAssignor> assignors = getAssignorInstances(
                  Arrays.asList(StickyAssignor.class.getName(), CooperativeStickyAssignor.class.getName()),
                  Collections.emptyMap()
          );
          assertInstanceOf(StickyAssignor.class, assignors.get(0));
          assertInstanceOf(CooperativeStickyAssignor.class, assignors.get(1));
      }
  
      @Test
      public void shouldThrowKafkaExceptionOnNonAssignor() {
          assertThrows(KafkaException.class, () -> getAssignorInstances(
                  Collections.singletonList(String.class.getName()),
                  Collections.emptyMap())
          );
      }
  
      @Test
      public void shouldThrowKafkaExceptionOnAssignorNotFound() {
          assertThrows(KafkaException.class, () -> getAssignorInstances(
                  Collections.singletonList("Non-existent assignor"),
                  Collections.emptyMap())
          );
      }
  
      @Test
      public void shouldInstantiateFromClassType() {
          List<String> classTypes =
                  initConsumerConfigWithClassTypes(Collections.singletonList(StickyAssignor.class))
                  .getList(ConsumerConfig.PARTITION_ASSIGNMENT_STRATEGY_CONFIG);
          List<ConsumerPartitionAssignor> assignors = getAssignorInstances(classTypes, Collections.emptyMap());
          assertInstanceOf(StickyAssignor.class, assignors.get(0));
      }
  
      @Test
      public void shouldInstantiateFromListOfClassTypes() {
          List<String> classTypes = initConsumerConfigWithClassTypes(
                  Arrays.asList(StickyAssignor.class, CooperativeStickyAssignor.class)
          ).getList(ConsumerConfig.PARTITION_ASSIGNMENT_STRATEGY_CONFIG);
  
          List<ConsumerPartitionAssignor> assignors = getAssignorInstances(classTypes, Collections.emptyMap());
  
          assertInstanceOf(StickyAssignor.class, assignors.get(0));
          assertInstanceOf(CooperativeStickyAssignor.class, assignors.get(1));
      }
  
      @Test
      public void shouldThrowKafkaExceptionOnListWithNonAssignorClassType() {
          List<String> classTypes =
                  initConsumerConfigWithClassTypes(Arrays.asList(StickyAssignor.class, String.class))
                  .getList(ConsumerConfig.PARTITION_ASSIGNMENT_STRATEGY_CONFIG);
  
          assertThrows(KafkaException.class, () -> getAssignorInstances(classTypes, Collections.emptyMap()));
      }
  
      @Test
      public void shouldThrowKafkaExceptionOnAssignorsWithSameName() {
          assertThrows(KafkaException.class, () -> getAssignorInstances(
              Arrays.asList(RangeAssignor.class.getName(), TestConsumerPartitionAssignor.class.getName()),
              Collections.emptyMap()
          ));
      }
  
      @Test
      public void shouldBeConfigurable() {
          Map<String, Object> configs = Collections.singletonMap("key", "value");
          List<ConsumerPartitionAssignor> assignors = getAssignorInstances(
              Collections.singletonList(TestConsumerPartitionAssignor.class.getName()),
              configs
          );
          assertEquals(1, assignors.size());
          assertInstanceOf(TestConsumerPartitionAssignor.class, assignors.get(0));
          assertEquals(configs, ((TestConsumerPartitionAssignor) assignors.get(0)).configs);
      }
  
  
      public static class TestConsumerPartitionAssignor implements ConsumerPartitionAssignor, Configurable {
          private Map<String, ?> configs = null;
  
          @Override
          public GroupAssignment assign(Cluster metadata, GroupSubscription groupSubscription) {
              return null;
          }
  
          @Override
          public String name() {
              // use the RangeAssignor's name to cause naming conflict
              return new RangeAssignor().name();
          }
  
          @Override
          public void configure(Map<String, ?> configs) {
              this.configs = configs;
          }
      }
  
      private ConsumerConfig initConsumerConfigWithClassTypes(List<Object> classTypes) {
          Properties props = new Properties();
          props.put(KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
          props.put(VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
          props.put(ConsumerConfig.PARTITION_ASSIGNMENT_STRATEGY_CONFIG, classTypes);
          props.put(ConsumerConfig.GROUP_PROTOCOL_CONFIG, GroupProtocol.CLASSIC.name());
          return new ConsumerConfig(props);
      }
  }
  