dajac commented on code in PR #13443: URL: https://github.com/apache/kafka/pull/13443#discussion_r1170021475
########## group-coordinator/src/test/java/org/apache/kafka/coordinator/group/assignor/RangeAssignorTest.java: ########## @@ -0,0 +1,416 @@ +/* + * 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.junit.jupiter.api.Test; + +import java.util.ArrayList; +import java.util.Arrays; +import java.util.Collections; +import java.util.HashMap; +import java.util.HashSet; +import java.util.List; +import java.util.Map; +import java.util.Optional; +import java.util.Set; + +import static org.junit.jupiter.api.Assertions.assertEquals; +import static org.junit.jupiter.api.Assertions.assertNull; +import static org.junit.jupiter.api.Assertions.assertTrue; + +public class RangeAssignorTest { + private final RangeAssignor assignor = new RangeAssignor(); + private final Uuid topic1Uuid = Uuid.randomUuid(); + private final Uuid topic2Uuid = Uuid.randomUuid(); + private final Uuid topic3Uuid = Uuid.randomUuid(); + private final String consumerA = "A"; + private final String consumerB = "B"; + private final String consumerC = "C"; + + @Test + public void testOneConsumerNoTopic() { + Map<Uuid, AssignmentTopicMetadata> topics = new HashMap<>(); + topics.put(topic1Uuid, new AssignmentTopicMetadata(3)); + Map<String, AssignmentMemberSpec> members = new HashMap<>(); + List<Uuid> subscribedTopics = new ArrayList<>(); + members.computeIfAbsent(consumerA, k -> new AssignmentMemberSpec(Optional.empty(), Optional.empty(), subscribedTopics, new HashMap<>())); + + AssignmentSpec assignmentSpec = new AssignmentSpec(members, topics); + GroupAssignment groupAssignment = assignor.assign(assignmentSpec); + + assertTrue(groupAssignment.members().isEmpty()); + } + + @Test + public void testOneConsumerNonExistentTopic() { + Map<Uuid, AssignmentTopicMetadata> topics = new HashMap<>(); + topics.put(topic1Uuid, new AssignmentTopicMetadata(3)); + Map<String, AssignmentMemberSpec> members = new HashMap<>(); + List<Uuid> subscribedTopics = new ArrayList<>(); + subscribedTopics.add(topic2Uuid); + members.computeIfAbsent(consumerA, k -> new AssignmentMemberSpec(Optional.empty(), Optional.empty(), subscribedTopics, new HashMap<>())); + + AssignmentSpec assignmentSpec = new AssignmentSpec(members, topics); + GroupAssignment groupAssignment = assignor.assign(assignmentSpec); + + assertTrue(groupAssignment.members().isEmpty()); + } + + @Test + public void testFirstAssignmentTwoConsumersTwoTopicsSameSubscriptions() { + // A -> T1, T3 // B -> T1, T3 // T1 -> 3 Partitions // T3 -> 2 Partitions + // Topics + Map<Uuid, AssignmentTopicMetadata> topics = new HashMap<>(); + topics.put(topic1Uuid, new AssignmentTopicMetadata(3)); + topics.put(topic3Uuid, new AssignmentTopicMetadata(2)); + // Members + Map<String, AssignmentMemberSpec> members = new HashMap<>(); + // Consumer A + List<Uuid> subscribedTopicsA = new ArrayList<>(Arrays.asList(topic1Uuid, topic3Uuid)); + members.put(consumerA, new AssignmentMemberSpec(Optional.empty(), Optional.empty(), subscribedTopicsA, new HashMap<>())); + // Consumer B + List<Uuid> subscribedTopicsB = new ArrayList<>(Arrays.asList(topic1Uuid, topic3Uuid)); + members.put(consumerB, new AssignmentMemberSpec(Optional.empty(), Optional.empty(), subscribedTopicsB, new HashMap<>())); + + AssignmentSpec assignmentSpec = new AssignmentSpec(members, topics); + GroupAssignment computedAssignment = assignor.assign(assignmentSpec); + + Map<Uuid, Set<Set<Integer>>> expectedAssignment = new HashMap<>(); + // Topic 1 Partitions Assignment + expectedAssignment.computeIfAbsent(topic1Uuid, k -> new HashSet<>()).add(new HashSet<>(Arrays.asList(0, 1))); + expectedAssignment.computeIfAbsent(topic1Uuid, k -> new HashSet<>()).add(new HashSet<>(Collections.singletonList(2))); + // Topic 3 Partitions Assignment + expectedAssignment.computeIfAbsent(topic3Uuid, k -> new HashSet<>()).add(new HashSet<>(Collections.singletonList(0))); + expectedAssignment.computeIfAbsent(topic3Uuid, k -> new HashSet<>()).add(new HashSet<>(Collections.singletonList(1))); + + assertAssignment(expectedAssignment, computedAssignment); + } + + @Test + public void testFirstAssignmentThreeConsumersThreeTopicsDifferentSubscriptions() { + // A -> T1, T2 // B -> T3 // C -> T2, T3 // T1 -> 3 Partitions // T2 -> 3 Partitions // T3 -> 2 Partitions + // Topics + Map<Uuid, AssignmentTopicMetadata> topics = new HashMap<>(); + topics.put(topic1Uuid, new AssignmentTopicMetadata(3)); + topics.put(topic2Uuid, new AssignmentTopicMetadata(3)); + topics.put(topic3Uuid, new AssignmentTopicMetadata(2)); + // Members + Map<String, AssignmentMemberSpec> members = new HashMap<>(); + // Consumer A + List<Uuid> subscribedTopicsA = new ArrayList<>(Arrays.asList(topic1Uuid, topic2Uuid)); + members.put(consumerA, new AssignmentMemberSpec(Optional.empty(), Optional.empty(), subscribedTopicsA, new HashMap<>())); + // Consumer B + List<Uuid> subscribedTopicsB = new ArrayList<>(Collections.singletonList(topic3Uuid)); + members.put(consumerB, new AssignmentMemberSpec(Optional.empty(), Optional.empty(), subscribedTopicsB, new HashMap<>())); + // Consumer C + List<Uuid> subscribedTopicsC = new ArrayList<>(Arrays.asList(topic2Uuid, topic3Uuid)); + members.put(consumerC, new AssignmentMemberSpec(Optional.empty(), Optional.empty(), subscribedTopicsC, new HashMap<>())); + + AssignmentSpec assignmentSpec = new AssignmentSpec(members, topics); + GroupAssignment computedAssignment = assignor.assign(assignmentSpec); + + Map<Uuid, Set<Set<Integer>>> expectedAssignment = new HashMap<>(); + // Topic 1 Partitions Assignment + expectedAssignment.computeIfAbsent(topic1Uuid, k -> new HashSet<>()).add(new HashSet<>(Arrays.asList(0, 1, 2))); + // Topic 2 Partitions Assignment + expectedAssignment.computeIfAbsent(topic2Uuid, k -> new HashSet<>()).add(new HashSet<>(Arrays.asList(0, 1))); + expectedAssignment.computeIfAbsent(topic2Uuid, k -> new HashSet<>()).add(new HashSet<>(Collections.singletonList(2))); + // Topic 3 Partitions Assignment + expectedAssignment.computeIfAbsent(topic3Uuid, k -> new HashSet<>()).add(new HashSet<>(Collections.singletonList(0))); + expectedAssignment.computeIfAbsent(topic3Uuid, k -> new HashSet<>()).add(new HashSet<>(Collections.singletonList(1))); + + assertAssignment(expectedAssignment, computedAssignment); + } + + @Test + public void testFirstAssignmentNumConsumersGreaterThanNumPartitions() { + // Topics + Map<Uuid, AssignmentTopicMetadata> topics = new HashMap<>(); + topics.put(topic1Uuid, new AssignmentTopicMetadata(3)); + // Topic 3 has 2 partitions but three consumers subscribed to it - one of them will not get an assignment + topics.put(topic3Uuid, new AssignmentTopicMetadata(2)); + // Members + Map<String, AssignmentMemberSpec> members = new HashMap<>(); + // Consumer A + List<Uuid> subscribedTopicsA = new ArrayList<>(Arrays.asList(topic1Uuid, topic3Uuid)); + members.put(consumerA, new AssignmentMemberSpec(Optional.empty(), Optional.empty(), subscribedTopicsA, new HashMap<>())); + // Consumer B + List<Uuid> subscribedTopicsB = new ArrayList<>(Arrays.asList(topic1Uuid, topic3Uuid)); + members.put(consumerB, new AssignmentMemberSpec(Optional.empty(), Optional.empty(), subscribedTopicsB, new HashMap<>())); + // Consumer C + List<Uuid> subscribedTopicsC = new ArrayList<>(Arrays.asList(topic1Uuid, topic3Uuid)); + members.put(consumerC, new AssignmentMemberSpec(Optional.empty(), Optional.empty(), subscribedTopicsC, new HashMap<>())); + + AssignmentSpec assignmentSpec = new AssignmentSpec(members, topics); + GroupAssignment computedAssignment = assignor.assign(assignmentSpec); + + Map<Uuid, Set<Set<Integer>>> expectedAssignment = new HashMap<>(); + // Topic 1 Partitions Assignment + expectedAssignment.computeIfAbsent(topic1Uuid, k -> new HashSet<>()).add(new HashSet<>(Collections.singletonList(0))); + expectedAssignment.computeIfAbsent(topic1Uuid, k -> new HashSet<>()).add(new HashSet<>(Collections.singletonList(1))); + expectedAssignment.computeIfAbsent(topic1Uuid, k -> new HashSet<>()).add(new HashSet<>(Collections.singletonList(2))); + // Topic 2 Partitions Assignment + expectedAssignment.computeIfAbsent(topic3Uuid, k -> new HashSet<>()).add(new HashSet<>(Collections.singletonList(0))); + expectedAssignment.computeIfAbsent(topic3Uuid, k -> new HashSet<>()).add(new HashSet<>(Collections.singletonList(1))); + + assertAssignment(expectedAssignment, computedAssignment); + } + + @Test + public void testReassignmentNumConsumersGreaterThanNumPartitionsWhenOneConsumerAdded() { + // Topics + Map<Uuid, AssignmentTopicMetadata> topics = new HashMap<>(); + topics.put(topic1Uuid, new AssignmentTopicMetadata(2)); + topics.put(topic2Uuid, new AssignmentTopicMetadata(2)); + // Members + Map<String, AssignmentMemberSpec> members = new HashMap<>(); + // Add a new consumer to trigger a re-assignment + // Consumer C + List<Uuid> subscribedTopicsC = new ArrayList<>(Arrays.asList(topic1Uuid, topic2Uuid)); + members.put(consumerC, new AssignmentMemberSpec(Optional.empty(), Optional.empty(), subscribedTopicsC, new HashMap<>())); + // Consumer A + List<Uuid> subscribedTopicsA = new ArrayList<>(Arrays.asList(topic1Uuid, topic2Uuid)); + Map<Uuid, Set<Integer>> currentAssignmentForA = new HashMap<>(); + currentAssignmentForA.put(topic1Uuid, new HashSet<>(Collections.singletonList(0))); + currentAssignmentForA.put(topic2Uuid, new HashSet<>(Collections.singletonList(0))); + members.computeIfAbsent(consumerA, k -> new AssignmentMemberSpec(Optional.empty(), Optional.empty(), subscribedTopicsA, currentAssignmentForA)); + // Consumer B + List<Uuid> subscribedTopicsB = new ArrayList<>(Arrays.asList(topic1Uuid, topic2Uuid)); + Map<Uuid, Set<Integer>> currentAssignmentForB = new HashMap<>(); + currentAssignmentForB.put(topic1Uuid, new HashSet<>(Collections.singletonList(1))); + currentAssignmentForB.put(topic2Uuid, new HashSet<>(Collections.singletonList(1))); + members.computeIfAbsent(consumerB, k -> new AssignmentMemberSpec(Optional.empty(), Optional.empty(), subscribedTopicsB, currentAssignmentForB)); + + AssignmentSpec assignmentSpec = new AssignmentSpec(members, topics); + GroupAssignment computedAssignment = assignor.assign(assignmentSpec); + + Map<Uuid, Set<Set<Integer>>> expectedAssignment = new HashMap<>(); + // Topic 1 Partitions Assignment + expectedAssignment.computeIfAbsent(topic1Uuid, k -> new HashSet<>()).add(new HashSet<>(Collections.singletonList(0))); + expectedAssignment.computeIfAbsent(topic1Uuid, k -> new HashSet<>()).add(new HashSet<>(Collections.singletonList(1))); + // Topic 2 Partitions Assignment + expectedAssignment.computeIfAbsent(topic2Uuid, k -> new HashSet<>()).add(new HashSet<>(Collections.singletonList(0))); + expectedAssignment.computeIfAbsent(topic2Uuid, k -> new HashSet<>()).add(new HashSet<>(Collections.singletonList(1))); + + // Test for stickiness + assertEquals(computedAssignment.members().get(consumerA).targetPartitions(), new HashMap<>(currentAssignmentForA), "Stickiness test failed for Consumer A"); + assertEquals(computedAssignment.members().get(consumerB).targetPartitions(), new HashMap<>(currentAssignmentForB), "Stickiness test failed for Consumer B"); + + // Consumer C shouldn't get any assignment, due to stickiness A, B retain their assignments + assertNull(computedAssignment.members().get(consumerC)); + assertAssignment(expectedAssignment, computedAssignment); + assertCoPartitionJoinProperty(computedAssignment); + } + + @Test + public void testReassignmentWhenOnePartitionAddedForTwoConsumersTwoTopics() { + // T1, T2 both have 3 partitions each when first assignment was calculated -> currentAssignmentForX + Map<String, AssignmentMemberSpec> members = new HashMap<>(); + // Consumer A + List<Uuid> subscribedTopicsA = new ArrayList<>(Arrays.asList(topic1Uuid, topic2Uuid)); + Map<Uuid, Set<Integer>> currentAssignmentForA = new HashMap<>(); + currentAssignmentForA.put(topic1Uuid, new HashSet<>(Arrays.asList(0, 1))); + currentAssignmentForA.put(topic2Uuid, new HashSet<>(Arrays.asList(0, 1))); + members.computeIfAbsent(consumerA, k -> new AssignmentMemberSpec(Optional.empty(), Optional.empty(), subscribedTopicsA, currentAssignmentForA)); + + // Consumer B + List<Uuid> subscribedTopicsB = new ArrayList<>(Arrays.asList(topic1Uuid, topic2Uuid)); + Map<Uuid, Set<Integer>> currentAssignmentForB = new HashMap<>(); + currentAssignmentForB.put(topic1Uuid, new HashSet<>(Collections.singletonList(2))); + currentAssignmentForB.put(topic2Uuid, new HashSet<>(Collections.singletonList(2))); + members.computeIfAbsent(consumerB, k -> new AssignmentMemberSpec(Optional.empty(), Optional.empty(), subscribedTopicsB, currentAssignmentForB)); + + // Simulating adding a partition - originally T1 -> 3 Partitions and T2 -> 3 Partitions + Map<Uuid, AssignmentTopicMetadata> topics = new HashMap<>(); + topics.put(topic1Uuid, new AssignmentTopicMetadata(4)); + topics.put(topic2Uuid, new AssignmentTopicMetadata(4)); + + AssignmentSpec assignmentSpec = new AssignmentSpec(members, topics); + GroupAssignment computedAssignment = assignor.assign(assignmentSpec); + + Map<Uuid, Set<Set<Integer>>> expectedAssignment = new HashMap<>(); + // Topic 1 Partitions Assignment + expectedAssignment.computeIfAbsent(topic1Uuid, k -> new HashSet<>()).add(new HashSet<>(Arrays.asList(0, 1))); + expectedAssignment.computeIfAbsent(topic1Uuid, k -> new HashSet<>()).add(new HashSet<>(Arrays.asList(2, 3))); + // Topic 2 Partitions Assignment + expectedAssignment.computeIfAbsent(topic2Uuid, k -> new HashSet<>()).add(new HashSet<>(Arrays.asList(0, 1))); + expectedAssignment.computeIfAbsent(topic2Uuid, k -> new HashSet<>()).add(new HashSet<>(Arrays.asList(2, 3))); + + // Test for stickiness + assertEquals(computedAssignment.members().get(consumerA).targetPartitions(), new HashMap<>(currentAssignmentForA), "Stickiness test failed for Consumer A"); + // Implicitly B also retained its partitions since the other set of assigned partitions is (2,3) + + assertAssignment(expectedAssignment, computedAssignment); + assertCoPartitionJoinProperty(computedAssignment); + } + + @Test + public void testReassignmentWhenOneConsumerAddedAfterInitialAssignmentWithTwoConsumersTwoTopics() { + Map<Uuid, AssignmentTopicMetadata> topics = new HashMap<>(); + topics.put(topic1Uuid, new AssignmentTopicMetadata(3)); + topics.put(topic2Uuid, new AssignmentTopicMetadata(3)); + + Map<String, AssignmentMemberSpec> members = new HashMap<>(); + // Consumer A + List<Uuid> subscribedTopicsA = new ArrayList<>(Arrays.asList(topic1Uuid, topic2Uuid)); + Map<Uuid, Set<Integer>> currentAssignmentForA = new HashMap<>(); + currentAssignmentForA.put(topic1Uuid, new HashSet<>(Arrays.asList(0, 1))); + currentAssignmentForA.put(topic2Uuid, new HashSet<>(Arrays.asList(0, 1))); + members.computeIfAbsent(consumerA, k -> new AssignmentMemberSpec(Optional.empty(), Optional.empty(), subscribedTopicsA, currentAssignmentForA)); + // Consumer B + List<Uuid> subscribedTopicsB = new ArrayList<>(Arrays.asList(topic1Uuid, topic2Uuid)); + Map<Uuid, Set<Integer>> currentAssignmentForB = new HashMap<>(); + currentAssignmentForB.put(topic1Uuid, new HashSet<>(Collections.singletonList(2))); + currentAssignmentForB.put(topic2Uuid, new HashSet<>(Collections.singletonList(2))); + members.computeIfAbsent(consumerB, k -> new AssignmentMemberSpec(Optional.empty(), Optional.empty(), subscribedTopicsB, currentAssignmentForB)); + // Add a new consumer to trigger a re-assignment + // Consumer C + List<Uuid> subscribedTopicsC = new ArrayList<>(Arrays.asList(topic1Uuid, topic2Uuid)); + members.put(consumerC, new AssignmentMemberSpec(Optional.empty(), Optional.empty(), subscribedTopicsC, new HashMap<>())); + + AssignmentSpec assignmentSpec = new AssignmentSpec(members, topics); + GroupAssignment computedAssignment = assignor.assign(assignmentSpec); + + Map<Uuid, Set<Set<Integer>>> expectedAssignment = new HashMap<>(); + // Topic 1 Partitions Assignment + expectedAssignment.computeIfAbsent(topic1Uuid, k -> new HashSet<>()).add(new HashSet<>(Collections.singletonList(0))); + expectedAssignment.computeIfAbsent(topic1Uuid, k -> new HashSet<>()).add(new HashSet<>(Collections.singletonList(2))); + expectedAssignment.computeIfAbsent(topic1Uuid, k -> new HashSet<>()).add(new HashSet<>(Collections.singletonList(1))); + // Topic 2 Partitions Assignment + expectedAssignment.computeIfAbsent(topic2Uuid, k -> new HashSet<>()).add(new HashSet<>(Collections.singletonList(0))); + expectedAssignment.computeIfAbsent(topic2Uuid, k -> new HashSet<>()).add(new HashSet<>(Collections.singletonList(2))); + expectedAssignment.computeIfAbsent(topic2Uuid, k -> new HashSet<>()).add(new HashSet<>(Collections.singletonList(1))); + + // Test for stickiness + assertEquals(computedAssignment.members().get(consumerB).targetPartitions(), new HashMap<>(currentAssignmentForB), "Stickiness test failed for Consumer B"); + assertTrue(computedAssignment.members().get(consumerA).targetPartitions().get(topic1Uuid).contains(0), "Stickiness test failed for Consumer A"); + // Co-partition join property test ensures that A retained the same partition for all topics. + + assertAssignment(expectedAssignment, computedAssignment); + assertCoPartitionJoinProperty(computedAssignment); + } + + @Test + public void testReassignmentWhenOneConsumerRemovedAfterInitialAssignmentWithTwoConsumersTwoTopics() { + Map<Uuid, AssignmentTopicMetadata> topics = new HashMap<>(); + topics.put(topic1Uuid, new AssignmentTopicMetadata(3)); + topics.put(topic2Uuid, new AssignmentTopicMetadata(3)); + + Map<String, AssignmentMemberSpec> members = new HashMap<>(); + // Consumer A was removed + + // Consumer B + List<Uuid> subscribedTopicsB = new ArrayList<>(Arrays.asList(topic1Uuid, topic2Uuid)); + Map<Uuid, Set<Integer>> currentAssignmentForB = new HashMap<>(); + currentAssignmentForB.put(topic1Uuid, new HashSet<>(Collections.singletonList(2))); + currentAssignmentForB.put(topic2Uuid, new HashSet<>(Collections.singletonList(2))); + members.computeIfAbsent(consumerB, k -> new AssignmentMemberSpec(Optional.empty(), Optional.empty(), subscribedTopicsB, currentAssignmentForB)); + + AssignmentSpec assignmentSpec = new AssignmentSpec(members, topics); + GroupAssignment computedAssignment = assignor.assign(assignmentSpec); + + Map<Uuid, Set<Set<Integer>>> expectedAssignment = new HashMap<>(); + // Topic 1 Partitions Assignment + expectedAssignment.computeIfAbsent(topic1Uuid, k -> new HashSet<>()).add(new HashSet<>(Arrays.asList(0, 1, 2))); + // Topic 2 Partitions Assignment + expectedAssignment.computeIfAbsent(topic2Uuid, k -> new HashSet<>()).add(new HashSet<>(Arrays.asList(0, 1, 2))); + + assertAssignment(expectedAssignment, computedAssignment); + assertCoPartitionJoinProperty(computedAssignment); + } + + @Test + public void testReassignmentWhenMultipleSubscriptionsRemovedAfterInitialAssignmentWithThreeConsumersTwoTopics() { + + Map<Uuid, AssignmentTopicMetadata> topics = new HashMap<>(); + topics.put(topic1Uuid, new AssignmentTopicMetadata(3)); + topics.put(topic2Uuid, new AssignmentTopicMetadata(3)); + topics.put(topic3Uuid, new AssignmentTopicMetadata(2)); + + // Let initial subscriptions be A -> T1, T2 // B -> T2 // C -> T2, T3 + // Change the subscriptions to A -> T1 // B -> T1, T2, T3 // C -> T2 + Map<String, AssignmentMemberSpec> members = new HashMap<>(); + // Consumer A + Map<Uuid, Set<Integer>> currentAssignmentForA = new HashMap<>(); + currentAssignmentForA.put(topic1Uuid, new HashSet<>(Arrays.asList(0, 1, 2))); + currentAssignmentForA.put(topic2Uuid, new HashSet<>(Collections.singletonList(0))); + // Change subscriptions + List<Uuid> subscribedTopicsA = new ArrayList<>(Collections.singletonList(topic1Uuid)); + members.computeIfAbsent(consumerA, k -> new AssignmentMemberSpec(Optional.empty(), Optional.empty(), subscribedTopicsA, currentAssignmentForA)); + // Consumer B + Map<Uuid, Set<Integer>> currentAssignmentForB = new HashMap<>(); + currentAssignmentForB.put(topic2Uuid, new HashSet<>(Collections.singletonList(1))); + // Change subscriptions + List<Uuid> subscribedTopicsB = new ArrayList<>(Arrays.asList(topic1Uuid, topic2Uuid, topic3Uuid)); + members.computeIfAbsent(consumerB, k -> new AssignmentMemberSpec(Optional.empty(), Optional.empty(), subscribedTopicsB, currentAssignmentForB)); + // Consumer C + Map<Uuid, Set<Integer>> currentAssignmentForC = new HashMap<>(); + currentAssignmentForC.put(topic2Uuid, new HashSet<>(Collections.singletonList(2))); + currentAssignmentForC.put(topic3Uuid, new HashSet<>(Arrays.asList(0, 1))); + // Change subscriptions + List<Uuid> subscribedTopicsC = new ArrayList<>(Collections.singletonList(topic2Uuid)); + members.put(consumerC, new AssignmentMemberSpec(Optional.empty(), Optional.empty(), subscribedTopicsC, new HashMap<>())); + + AssignmentSpec assignmentSpec = new AssignmentSpec(members, topics); + GroupAssignment computedAssignment = assignor.assign(assignmentSpec); + + Map<Uuid, Set<Set<Integer>>> expectedAssignment = new HashMap<>(); + // Topic 1 Partitions Assignment + expectedAssignment.computeIfAbsent(topic1Uuid, k -> new HashSet<>()).add(new HashSet<>(Arrays.asList(0, 1))); + expectedAssignment.computeIfAbsent(topic1Uuid, k -> new HashSet<>()).add(new HashSet<>(Collections.singletonList(2))); + // Topic 2 Partitions Assignment + expectedAssignment.computeIfAbsent(topic2Uuid, k -> new HashSet<>()).add(new HashSet<>(Arrays.asList(0, 1))); + expectedAssignment.computeIfAbsent(topic2Uuid, k -> new HashSet<>()).add(new HashSet<>(Collections.singletonList(2))); + // Topic 3 Partitions Assignment + expectedAssignment.computeIfAbsent(topic3Uuid, k -> new HashSet<>()).add(new HashSet<>(Arrays.asList(0, 1))); + + // Test for stickiness + assertTrue(computedAssignment.members().get(consumerC).targetPartitions().get(topic2Uuid).contains(2), "Stickiness test failed for Consumer C"); + assertTrue(computedAssignment.members().get(consumerA).targetPartitions().get(topic1Uuid).containsAll(Arrays.asList(0, 1)), "Stickiness test failed for Consumer A"); + + assertAssignment(expectedAssignment, computedAssignment); Review Comment: I wonder if it would be better to actually create the expected `GroupAssignment` and to compare the computed one against it. We could then just use `assertEquals` and this would verify the full output. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: jira-unsubscr...@kafka.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org