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.coordinator.group.assignor;
  
  import org.apache.kafka.common.Uuid;
  import org.apache.kafka.coordinator.group.MetadataImageBuilder;
  import org.apache.kafka.coordinator.group.api.assignor.GroupAssignment;
  import org.apache.kafka.coordinator.group.api.assignor.GroupSpec;
  import org.apache.kafka.coordinator.group.api.assignor.PartitionAssignorException;
  import org.apache.kafka.coordinator.group.api.assignor.SubscriptionType;
  import org.apache.kafka.coordinator.group.modern.Assignment;
  import org.apache.kafka.coordinator.group.modern.GroupSpecImpl;
  import org.apache.kafka.coordinator.group.modern.MemberSubscriptionAndAssignmentImpl;
  import org.apache.kafka.coordinator.group.modern.SubscribedTopicDescriberImpl;
  import org.apache.kafka.image.MetadataImage;
  
  import org.junit.jupiter.api.Test;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.Optional;
  import java.util.Set;
  import java.util.TreeMap;
  
  import static org.apache.kafka.coordinator.group.AssignmentTestUtil.assertAssignment;
  import static org.apache.kafka.coordinator.group.AssignmentTestUtil.invertedTargetAssignment;
  import static org.apache.kafka.coordinator.group.AssignmentTestUtil.mkAssignment;
  import static org.apache.kafka.coordinator.group.AssignmentTestUtil.mkTopicAssignment;
  import static org.apache.kafka.coordinator.group.api.assignor.SubscriptionType.HETEROGENEOUS;
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  
  public class UniformHeterogeneousAssignmentBuilderTest {
      private final UniformAssignor assignor = new UniformAssignor();
      private final Uuid topic1Uuid = Uuid.fromString("T1-A4s3VTwiI5CTbEp6POw");
      private final Uuid topic2Uuid = Uuid.fromString("T2-B4s3VTwiI5YHbPp6YUe");
      private final Uuid topic3Uuid = Uuid.fromString("T3-CU8fVTLCz5YMkLoDQsa");
      private final Uuid topic4Uuid = Uuid.fromString("T4-Tw9fVTLCz5HbPp6YQsa");
      private final String topic1Name = "topic1";
      private final String topic2Name = "topic2";
      private final String topic3Name = "topic3";
      private final String topic4Name = "topic4";
      private final String memberA = "A";
      private final String memberB = "B";
      private final String memberC = "C";
  
      /**
       * A GroupSpec implementation that returns members in sorted order, so that assignor output is
       * deterministic.
       */
      private static class TestGroupSpecImpl extends GroupSpecImpl {
          private final List<String> orderedMembers;
  
          public TestGroupSpecImpl(
              Map<String, MemberSubscriptionAndAssignmentImpl> members,
              SubscriptionType subscriptionType,
              Map<Uuid, Map<Integer, String>> invertedMemberAssignment
          ) {
              super(members, subscriptionType, invertedMemberAssignment);
  
              this.orderedMembers = new ArrayList<>(members.keySet());
              this.orderedMembers.sort(null);
          }
  
          /**
           * {@inheritDoc}
           */
          @Override
          public Collection<String> memberIds() {
              return orderedMembers;
          }
      }
  
      @Test
      public void testTwoMembersNoTopicSubscription() {
          MetadataImage metadataImage = new MetadataImageBuilder()
              .addTopic(topic1Uuid, topic1Name, 3)
              .build();
          SubscribedTopicDescriberImpl subscribedTopicMetadata = new SubscribedTopicDescriberImpl(
              metadataImage
          );
  
          Map<String, MemberSubscriptionAndAssignmentImpl> members = new TreeMap<>();
          members.put(memberA, new MemberSubscriptionAndAssignmentImpl(
              Optional.empty(),
              Optional.empty(),
              Set.of(),
              Assignment.EMPTY
          ));
          members.put(memberB, new MemberSubscriptionAndAssignmentImpl(
              Optional.empty(),
              Optional.empty(),
              Set.of(),
              Assignment.EMPTY
          ));
  
          GroupSpec groupSpec = new TestGroupSpecImpl(
              members,
              HETEROGENEOUS,
              Map.of()
          );
  
          GroupAssignment groupAssignment = assignor.assign(
              groupSpec,
              subscribedTopicMetadata
          );
  
          assertEquals(Map.of(), groupAssignment.members());
      }
  
      @Test
      public void testTwoMembersSubscribedToNonexistentTopics() {
          MetadataImage metadataImage = new MetadataImageBuilder()
              .addTopic(topic1Uuid, topic1Name, 3)
              .build();
          SubscribedTopicDescriberImpl subscribedTopicMetadata = new SubscribedTopicDescriberImpl(
              metadataImage
          );
  
          Map<String, MemberSubscriptionAndAssignmentImpl> members = new TreeMap<>();
          members.put(memberA, new MemberSubscriptionAndAssignmentImpl(
              Optional.empty(),
              Optional.empty(),
              Set.of(topic3Uuid),
              Assignment.EMPTY
          ));
          members.put(memberB, new MemberSubscriptionAndAssignmentImpl(
              Optional.empty(),
              Optional.empty(),
              Set.of(topic2Uuid),
              Assignment.EMPTY
          ));
  
          GroupSpec groupSpec = new TestGroupSpecImpl(
              members,
              HETEROGENEOUS,
              Map.of()
          );
  
          assertThrows(
              PartitionAssignorException.class,
              () -> assignor.assign(groupSpec, subscribedTopicMetadata));
      }
  
      @Test
      public void testFirstAssignmentTwoMembersTwoTopics() {
          MetadataImage metadataImage = new MetadataImageBuilder()
              .addTopic(topic1Uuid, topic1Name, 3)
              .addTopic(topic3Uuid, topic3Name, 6)
              .build();
  
          Map<String, MemberSubscriptionAndAssignmentImpl> members = new TreeMap<>();
  
          members.put(memberA, new MemberSubscriptionAndAssignmentImpl(
              Optional.empty(),
              Optional.empty(),
              Set.of(topic1Uuid, topic3Uuid),
              Assignment.EMPTY
          ));
  
          members.put(memberB, new MemberSubscriptionAndAssignmentImpl(
              Optional.empty(),
              Optional.empty(),
              Set.of(topic3Uuid),
              Assignment.EMPTY
          ));
  
          GroupSpec groupSpec = new TestGroupSpecImpl(
              members,
              HETEROGENEOUS,
              Map.of()
          );
          SubscribedTopicDescriberImpl subscribedTopicMetadata = new SubscribedTopicDescriberImpl(
              metadataImage
          );
  
          GroupAssignment computedAssignment = assignor.assign(
              groupSpec,
              subscribedTopicMetadata
          );
  
          Map<String, Map<Uuid, Set<Integer>>> expectedAssignment = new HashMap<>();
          expectedAssignment.put(memberA, mkAssignment(
              mkTopicAssignment(topic1Uuid, 0, 1, 2),
              mkTopicAssignment(topic3Uuid, 4)
          ));
          expectedAssignment.put(memberB, mkAssignment(
              mkTopicAssignment(topic3Uuid, 0, 1, 2, 3, 5)
          ));
  
          assertAssignment(expectedAssignment, computedAssignment);
      }
  
      @Test
      public void testFirstAssignmentNumMembersGreaterThanTotalNumPartitions() {
          MetadataImage metadataImage = new MetadataImageBuilder()
              .addTopic(topic1Uuid, topic1Name, 2)
              .addTopic(topic3Uuid, topic3Name, 1)
              .build();
  
          Map<String, MemberSubscriptionAndAssignmentImpl> members = new TreeMap<>();
  
          members.put(memberA, new MemberSubscriptionAndAssignmentImpl(
              Optional.empty(),
              Optional.empty(),
              Set.of(topic3Uuid),
              Assignment.EMPTY
          ));
  
          members.put(memberB, new MemberSubscriptionAndAssignmentImpl(
              Optional.empty(),
              Optional.empty(),
              Set.of(topic3Uuid),
              Assignment.EMPTY
          ));
  
          members.put(memberC, new MemberSubscriptionAndAssignmentImpl(
              Optional.empty(),
              Optional.empty(),
              Set.of(topic1Uuid),
              Assignment.EMPTY
          ));
  
          GroupSpec groupSpec = new TestGroupSpecImpl(
              members,
              HETEROGENEOUS,
              Map.of()
          );
          SubscribedTopicDescriberImpl subscribedTopicMetadata = new SubscribedTopicDescriberImpl(
              metadataImage
          );
  
          GroupAssignment computedAssignment = assignor.assign(
              groupSpec,
              subscribedTopicMetadata
          );
  
          // Topic 3 has 2 partitions but three members subscribed to it - one of them should not get an assignment.
          Map<String, Map<Uuid, Set<Integer>>> expectedAssignment = new HashMap<>();
          expectedAssignment.put(memberA, mkAssignment(
              mkTopicAssignment(topic3Uuid, 0)
          ));
          expectedAssignment.put(memberB,
              Map.of()
          );
          expectedAssignment.put(memberC, mkAssignment(
              mkTopicAssignment(topic1Uuid, 0, 1)
          ));
  
          assertAssignment(expectedAssignment, computedAssignment);
      }
  
      @Test
      public void testReassignmentForTwoMembersThreeTopicsGivenUnbalancedPrevAssignment() {
          MetadataImage metadataImage = new MetadataImageBuilder()
              .addTopic(topic1Uuid, topic1Name, 6)
              .addTopic(topic2Uuid, topic2Name, 4)
              .addTopic(topic3Uuid, topic3Name, 4)
              .build();
  
          Map<String, MemberSubscriptionAndAssignmentImpl> members = new TreeMap<>();
  
          members.put(memberA, new MemberSubscriptionAndAssignmentImpl(
              Optional.empty(),
              Optional.empty(),
              Set.of(topic1Uuid),
              new Assignment(mkAssignment(
                  mkTopicAssignment(topic1Uuid, 0, 1, 2)
              ))
          ));
  
          members.put(memberB, new MemberSubscriptionAndAssignmentImpl(
              Optional.empty(),
              Optional.empty(),
              Set.of(topic1Uuid, topic2Uuid),
              new Assignment(mkAssignment(
                  mkTopicAssignment(topic1Uuid, 3),
                  mkTopicAssignment(topic2Uuid, 0)
              ))
          ));
  
          members.put(memberC, new MemberSubscriptionAndAssignmentImpl(
              Optional.empty(),
              Optional.empty(),
              Set.of(topic1Uuid, topic2Uuid, topic3Uuid),
              new Assignment(mkAssignment(
                  mkTopicAssignment(topic1Uuid, 4, 5),
                  mkTopicAssignment(topic2Uuid, 1, 2, 3),
                  mkTopicAssignment(topic3Uuid, 0, 1, 2, 3)
              ))
          ));
  
          GroupSpec groupSpec = new TestGroupSpecImpl(
              members,
              HETEROGENEOUS,
              invertedTargetAssignment(members)
          );
          SubscribedTopicDescriberImpl subscribedTopicMetadata = new SubscribedTopicDescriberImpl(
              metadataImage
          );
  
          GroupAssignment computedAssignment = assignor.assign(
              groupSpec,
              subscribedTopicMetadata
          );
  
          Map<String, Map<Uuid, Set<Integer>>> expectedAssignment = new HashMap<>();
          expectedAssignment.put(memberA, mkAssignment(
              mkTopicAssignment(topic1Uuid, 0, 1, 2, 5)
          ));
          expectedAssignment.put(memberB, mkAssignment(
              mkTopicAssignment(topic1Uuid, 3),
              mkTopicAssignment(topic2Uuid, 0, 1, 2, 3)
          ));
          expectedAssignment.put(memberC, mkAssignment(
              mkTopicAssignment(topic1Uuid, 4),
              mkTopicAssignment(topic3Uuid, 0, 1, 2, 3)
          ));
  
          assertAssignment(expectedAssignment, computedAssignment);
      }
  
      @Test
      public void testReassignmentWhenPartitionsAreAddedForTwoMembers() {
          // Simulating adding partitions to T1, T2, T3 - originally T1 -> 4, T2 -> 3, T3 -> 2, T4 -> 3
          MetadataImage metadataImage = new MetadataImageBuilder()
              .addTopic(topic1Uuid, topic1Name, 6)
              .addTopic(topic2Uuid, topic2Name, 5)
              .addTopic(topic3Uuid, topic3Name, 3)
              .addTopic(topic4Uuid, topic4Name, 3)
              .build();
  
  
  
          Map<String, MemberSubscriptionAndAssignmentImpl> members = new TreeMap<>();
  
          members.put(memberA, new MemberSubscriptionAndAssignmentImpl(
              Optional.empty(),
              Optional.empty(),
              Set.of(topic1Uuid, topic3Uuid),
              new Assignment(mkAssignment(
                  mkTopicAssignment(topic1Uuid, 0, 1, 2, 3),
                  mkTopicAssignment(topic3Uuid, 0, 1)
              ))
          ));
  
          members.put(memberB, new MemberSubscriptionAndAssignmentImpl(
              Optional.empty(),
              Optional.empty(),
              Set.of(topic1Uuid, topic2Uuid, topic3Uuid, topic4Uuid),
              new Assignment(mkAssignment(
                  mkTopicAssignment(topic2Uuid, 0, 1, 2),
                  mkTopicAssignment(topic4Uuid, 0, 1, 2)
              ))
          ));
  
          GroupSpec groupSpec = new TestGroupSpecImpl(
              members,
              HETEROGENEOUS,
              invertedTargetAssignment(members)
          );
          SubscribedTopicDescriberImpl subscribedTopicMetadata = new SubscribedTopicDescriberImpl(
              metadataImage
          );
  
          GroupAssignment computedAssignment = assignor.assign(
              groupSpec,
              subscribedTopicMetadata
          );
  
          Map<String, Map<Uuid, Set<Integer>>> expectedAssignment = new HashMap<>();
          expectedAssignment.put(memberA, mkAssignment(
              mkTopicAssignment(topic1Uuid, 0, 1, 2, 3, 4, 5),
              mkTopicAssignment(topic3Uuid, 0, 1, 2)
          ));
          expectedAssignment.put(memberB, mkAssignment(
              mkTopicAssignment(topic2Uuid, 0, 1, 2, 3, 4),
              mkTopicAssignment(topic4Uuid, 0, 1, 2)
          ));
  
          assertAssignment(expectedAssignment, computedAssignment);
      }
  
      @Test
      public void testReassignmentWhenOneMemberAddedAndPartitionsAddedTwoMembersTwoTopics() {
          // Initially T1 -> 3, T2 -> 3 partitions.
          MetadataImage metadataImage = new MetadataImageBuilder()
              .addTopic(topic1Uuid, topic1Name, 6)
              .addTopic(topic2Uuid, topic2Name, 7)
              .build();
  
          Map<String, MemberSubscriptionAndAssignmentImpl> members = new TreeMap<>();
  
          members.put(memberA, new MemberSubscriptionAndAssignmentImpl(
              Optional.empty(),
              Optional.empty(),
              Set.of(topic1Uuid),
              new Assignment(mkAssignment(
                  mkTopicAssignment(topic1Uuid, 0, 2),
                  mkTopicAssignment(topic2Uuid, 0)
              ))
          ));
  
          members.put(memberB, new MemberSubscriptionAndAssignmentImpl(
              Optional.empty(),
              Optional.empty(),
              Set.of(topic1Uuid, topic2Uuid),
              new Assignment(mkAssignment(
                  mkTopicAssignment(topic1Uuid, 1),
                  mkTopicAssignment(topic2Uuid, 1, 2)
              ))
          ));
  
          // Add a new member to trigger a re-assignment.
          members.put(memberC, new MemberSubscriptionAndAssignmentImpl(
              Optional.empty(),
              Optional.empty(),
              Set.of(topic1Uuid, topic2Uuid),
              Assignment.EMPTY
          ));
  
          GroupSpec groupSpec = new TestGroupSpecImpl(
              members,
              HETEROGENEOUS,
              invertedTargetAssignment(members)
          );
          SubscribedTopicDescriberImpl subscribedTopicMetadata = new SubscribedTopicDescriberImpl(
              metadataImage
          );
  
          GroupAssignment computedAssignment = assignor.assign(
              groupSpec,
              subscribedTopicMetadata
          );
  
          Map<String, Map<Uuid, Set<Integer>>> expectedAssignment = new HashMap<>();
          expectedAssignment.put(memberA, mkAssignment(
              mkTopicAssignment(topic1Uuid, 0, 2, 3, 4, 5)
          ));
          expectedAssignment.put(memberB, mkAssignment(
              mkTopicAssignment(topic1Uuid, 1),
              mkTopicAssignment(topic2Uuid, 1, 2, 6)
          ));
          expectedAssignment.put(memberC, mkAssignment(
              mkTopicAssignment(topic2Uuid, 0, 3, 4, 5)
          ));
  
          assertAssignment(expectedAssignment, computedAssignment);
      }
  
      @Test
      public void testReassignmentWhenOneMemberRemovedAfterInitialAssignmentWithThreeMembersThreeTopics() {
          MetadataImage metadataImage = new MetadataImageBuilder()
              .addTopic(topic1Uuid, topic1Name, 3)
              .addTopic(topic2Uuid, topic2Name, 8)
              .addTopic(topic3Uuid, topic3Name, 3)
              .build();
  
          Map<String, MemberSubscriptionAndAssignmentImpl> members = new TreeMap<>();
  
          members.put(memberA, new MemberSubscriptionAndAssignmentImpl(
              Optional.empty(),
              Optional.empty(),
              Set.of(topic1Uuid, topic3Uuid),
              new Assignment(mkAssignment(
                  mkTopicAssignment(topic1Uuid, 0, 1, 2),
                  mkTopicAssignment(topic3Uuid, 0, 1)
              ))
          ));
  
          members.put(memberB, new MemberSubscriptionAndAssignmentImpl(
              Optional.empty(),
              Optional.empty(),
              Set.of(topic2Uuid),
              new Assignment(mkAssignment(
                  mkTopicAssignment(topic2Uuid, 3, 4, 5, 6)
              ))
          ));
  
          // Member C was removed
  
          GroupSpec groupSpec = new TestGroupSpecImpl(
              members,
              HETEROGENEOUS,
              invertedTargetAssignment(members)
          );
          SubscribedTopicDescriberImpl subscribedTopicMetadata = new SubscribedTopicDescriberImpl(
              metadataImage
          );
  
          GroupAssignment computedAssignment = assignor.assign(
              groupSpec,
              subscribedTopicMetadata
          );
  
          Map<String, Map<Uuid, Set<Integer>>> expectedAssignment = new HashMap<>();
          expectedAssignment.put(memberA, mkAssignment(
              mkTopicAssignment(topic1Uuid, 0, 1, 2),
              mkTopicAssignment(topic3Uuid, 0, 1, 2)
          ));
          expectedAssignment.put(memberB, mkAssignment(
              mkTopicAssignment(topic2Uuid, 0, 1, 2, 3, 4, 5, 6, 7)
          ));
  
          assertAssignment(expectedAssignment, computedAssignment);
      }
  
      @Test
      public void testReassignmentWhenOneSubscriptionRemovedAfterInitialAssignmentWithTwoMembersTwoTopics() {
          MetadataImage metadataImage = new MetadataImageBuilder()
              .addTopic(topic1Uuid, topic1Name, 3)
              .addTopic(topic2Uuid, topic2Name, 5)
              .build();
  
          // Initial subscriptions were [T1, T2]
          Map<String, MemberSubscriptionAndAssignmentImpl> members = new TreeMap<>();
  
          members.put(memberA, new MemberSubscriptionAndAssignmentImpl(
              Optional.empty(),
              Optional.empty(),
              Set.of(topic1Uuid),
              new Assignment(mkAssignment(
                  mkTopicAssignment(topic1Uuid, 0, 2),
                  mkTopicAssignment(topic2Uuid, 1, 3)
              ))
          ));
  
          members.put(memberB, new MemberSubscriptionAndAssignmentImpl(
              Optional.empty(),
              Optional.empty(),
              Set.of(topic1Uuid, topic2Uuid),
              new Assignment(mkAssignment(
                  mkTopicAssignment(topic1Uuid, 1),
                  mkTopicAssignment(topic2Uuid, 0, 2, 4)
              ))
          ));
  
          GroupSpec groupSpec = new TestGroupSpecImpl(
              members,
              HETEROGENEOUS,
              invertedTargetAssignment(members)
          );
          SubscribedTopicDescriberImpl subscribedTopicMetadata = new SubscribedTopicDescriberImpl(
              metadataImage
          );
  
          GroupAssignment computedAssignment = assignor.assign(
              groupSpec,
              subscribedTopicMetadata
          );
  
          Map<String, Map<Uuid, Set<Integer>>> expectedAssignment = new HashMap<>();
          expectedAssignment.put(memberA, mkAssignment(
              mkTopicAssignment(topic1Uuid, 0, 1, 2)
          ));
          expectedAssignment.put(memberB, mkAssignment(
              mkTopicAssignment(topic2Uuid, 0, 1, 2, 3, 4)
          ));
  
          assertAssignment(expectedAssignment, computedAssignment);
      }
  
      /**
       * Tests an edge case in the reassignment algorithm where we run out of topic partitions before
       * the topic's subscribers are balanced, and the topic's least loaded subscribers start off with
       * no partitions from the topic. The per-topic reassignment loop should break when it cannot
       * find a partition to reassign.
       */
      @Test
      public void testReassignmentWhenTopicPartitionsRunOutAndMembersHaveNoPartitions() {
          MetadataImage metadataImage = new MetadataImageBuilder()
              .addTopic(topic1Uuid, topic1Name, 2)
              .addTopic(topic2Uuid, topic2Name, 2)
              .addTopic(topic3Uuid, topic3Name, 2)
              .build();
  
          Map<String, MemberSubscriptionAndAssignmentImpl> members = new TreeMap<>();
  
          members.put(memberA, new MemberSubscriptionAndAssignmentImpl(
              Optional.empty(),
              Optional.empty(),
              Set.of(topic1Uuid, topic2Uuid, topic3Uuid),
              new Assignment(mkAssignment(
                  mkTopicAssignment(topic1Uuid, 0, 1),
                  mkTopicAssignment(topic2Uuid, 0, 1),
                  mkTopicAssignment(topic3Uuid, 0, 1)
              ))
          ));
  
          members.put(memberB, new MemberSubscriptionAndAssignmentImpl(
              Optional.empty(),
              Optional.empty(),
              Set.of(topic1Uuid, topic2Uuid, topic3Uuid),
              Assignment.EMPTY
          ));
  
          GroupSpec groupSpec = new TestGroupSpecImpl(
              members,
              HETEROGENEOUS,
              invertedTargetAssignment(members)
          );
          SubscribedTopicDescriberImpl subscribedTopicMetadata = new SubscribedTopicDescriberImpl(
              metadataImage
          );
  
          GroupAssignment computedAssignment = assignor.assign(
              groupSpec,
              subscribedTopicMetadata
          );
  
          Map<String, Map<Uuid, Set<Integer>>> expectedAssignment = new HashMap<>();
          expectedAssignment.put(memberA, mkAssignment(
              mkTopicAssignment(topic2Uuid, 0),
              mkTopicAssignment(topic3Uuid, 0, 1)
          ));
          expectedAssignment.put(memberB, mkAssignment(
              mkTopicAssignment(topic1Uuid, 0, 1),
              mkTopicAssignment(topic2Uuid, 1)
          ));
  
          assertAssignment(expectedAssignment, computedAssignment);
      }
  
      @Test
      public void testFirstAssignmentWithTwoMembersIncludingOneWithoutSubscriptions() {
          MetadataImage metadataImage = new MetadataImageBuilder()
              .addTopic(topic1Uuid, topic1Name, 3)
              .build();
  
          Map<String, MemberSubscriptionAndAssignmentImpl> members = new TreeMap<>();
  
          members.put(memberA, new MemberSubscriptionAndAssignmentImpl(
              Optional.empty(),
              Optional.empty(),
              Set.of(topic1Uuid),
              Assignment.EMPTY
          ));
  
          members.put(memberB, new MemberSubscriptionAndAssignmentImpl(
              Optional.empty(),
              Optional.empty(),
              Set.of(),
              Assignment.EMPTY
          ));
  
          GroupSpec groupSpec = new TestGroupSpecImpl(
              members,
              HETEROGENEOUS,
              Map.of()
          );
          SubscribedTopicDescriberImpl subscribedTopicMetadata = new SubscribedTopicDescriberImpl(
              metadataImage
          );
  
          GroupAssignment computedAssignment = assignor.assign(
              groupSpec,
              subscribedTopicMetadata
          );
  
          Map<String, Map<Uuid, Set<Integer>>> expectedAssignment = new HashMap<>();
          expectedAssignment.put(memberA, mkAssignment(
              mkTopicAssignment(topic1Uuid, 0, 1, 2)
          ));
          expectedAssignment.put(memberB, Map.of());
  
          assertAssignment(expectedAssignment, computedAssignment);
      }
  }
  