Adding upstream version 1.45.3+dfsg.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 3170 insertions, 0 deletions

diff --git a/src/fluent-bit/lib/librdkafka-2.1.0/tests/0113-cooperative_rebalance.cpp b/src/fluent-bit/lib/librdkafka-2.1.0/tests/0113-cooperative_rebalance.cpp
new file mode 100644
index 000000000..430798d7f
--- /dev/null
+++ b/src/fluent-bit/lib/librdkafka-2.1.0/tests/0113-cooperative_rebalance.cpp
@@ -0,0 +1,3170 @@
+/*
+ * librdkafka - Apache Kafka C library
+ *
+ * Copyright (c) 2020, Magnus Edenhill
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+extern "C" {
+#include "../src/rdkafka_protocol.h"
+#include "test.h"
+}
+#include <iostream>
+#include <map>
+#include <set>
+#include <algorithm>
+#include <cstring>
+#include <cstdlib>
+#include <assert.h>
+#include "testcpp.h"
+#include <fstream>
+
+using namespace std;
+
+/** Topic+Partition helper class */
+class Toppar {
+ public:
+  Toppar(const string &topic, int32_t partition) :
+      topic(topic), partition(partition) {
+  }
+
+  Toppar(const RdKafka::TopicPartition *tp) :
+      topic(tp->topic()), partition(tp->partition()) {
+  }
+
+  friend bool operator==(const Toppar &a, const Toppar &b) {
+    return a.partition == b.partition && a.topic == b.topic;
+  }
+
+  friend bool operator<(const Toppar &a, const Toppar &b) {
+    if (a.partition < b.partition)
+      return true;
+    return a.topic < b.topic;
+  }
+
+  string str() const {
+    return tostr() << topic << "[" << partition << "]";
+  }
+
+  std::string topic;
+  int32_t partition;
+};
+
+
+
+static std::string get_bootstrap_servers() {
+  RdKafka::Conf *conf;
+  std::string bootstrap_servers;
+  Test::conf_init(&conf, NULL, 0);
+  conf->get("bootstrap.servers", bootstrap_servers);
+  delete conf;
+  return bootstrap_servers;
+}
+
+
+class DrCb : public RdKafka::DeliveryReportCb {
+ public:
+  void dr_cb(RdKafka::Message &msg) {
+    if (msg.err())
+      Test::Fail("Delivery failed: " + RdKafka::err2str(msg.err()));
+  }
+};
+
+
+/**
+ * @brief Produce messages to partitions.
+ *
+ * The pair is Toppar,msg_cnt_per_partition.
+ * The Toppar is topic,partition_cnt.
+ */
+static void produce_msgs(vector<pair<Toppar, int> > partitions) {
+  RdKafka::Conf *conf;
+  Test::conf_init(&conf, NULL, 0);
+
+  string errstr;
+  DrCb dr;
+  conf->set("dr_cb", &dr, errstr);
+  RdKafka::Producer *p = RdKafka::Producer::create(conf, errstr);
+  if (!p)
+    Test::Fail("Failed to create producer: " + errstr);
+  delete conf;
+
+  for (vector<pair<Toppar, int> >::iterator it = partitions.begin();
+       it != partitions.end(); it++) {
+    for (int part = 0; part < it->first.partition; part++) {
+      for (int i = 0; i < it->second; i++) {
+        RdKafka::ErrorCode err =
+            p->produce(it->first.topic, part, RdKafka::Producer::RK_MSG_COPY,
+                       (void *)"Hello there", 11, NULL, 0, 0, NULL);
+        TEST_ASSERT(!err, "produce(%s, %d) failed: %s", it->first.topic.c_str(),
+                    part, RdKafka::err2str(err).c_str());
+
+        p->poll(0);
+      }
+    }
+  }
+
+  p->flush(10000);
+
+  delete p;
+}
+
+
+
+static RdKafka::KafkaConsumer *make_consumer(
+    string client_id,
+    string group_id,
+    string assignment_strategy,
+    vector<pair<string, string> > *additional_conf,
+    RdKafka::RebalanceCb *rebalance_cb,
+    int timeout_s) {
+  std::string bootstraps;
+  std::string errstr;
+  std::vector<std::pair<std::string, std::string> >::iterator itr;
+
+  RdKafka::Conf *conf;
+  Test::conf_init(&conf, NULL, timeout_s);
+  Test::conf_set(conf, "client.id", client_id);
+  Test::conf_set(conf, "group.id", group_id);
+  Test::conf_set(conf, "auto.offset.reset", "earliest");
+  Test::conf_set(conf, "enable.auto.commit", "false");
+  Test::conf_set(conf, "partition.assignment.strategy", assignment_strategy);
+  if (additional_conf != NULL) {
+    for (itr = (*additional_conf).begin(); itr != (*additional_conf).end();
+         itr++)
+      Test::conf_set(conf, itr->first, itr->second);
+  }
+
+  if (rebalance_cb) {
+    if (conf->set("rebalance_cb", rebalance_cb, errstr))
+      Test::Fail("Failed to set rebalance_cb: " + errstr);
+  }
+  RdKafka::KafkaConsumer *consumer =
+      RdKafka::KafkaConsumer::create(conf, errstr);
+  if (!consumer)
+    Test::Fail("Failed to create KafkaConsumer: " + errstr);
+  delete conf;
+
+  return consumer;
+}
+
+/**
+ * @returns a CSV string of the vector
+ */
+static string string_vec_to_str(const vector<string> &v) {
+  ostringstream ss;
+  for (vector<string>::const_iterator it = v.begin(); it != v.end(); it++)
+    ss << (it == v.begin() ? "" : ", ") << *it;
+  return ss.str();
+}
+
+void expect_assignment(RdKafka::KafkaConsumer *consumer, size_t count) {
+  std::vector<RdKafka::TopicPartition *> partitions;
+  RdKafka::ErrorCode err;
+  err = consumer->assignment(partitions);
+  if (err)
+    Test::Fail(consumer->name() +
+               " assignment() failed: " + RdKafka::err2str(err));
+  if (partitions.size() != count)
+    Test::Fail(tostr() << "Expecting consumer " << consumer->name()
+                       << " to have " << count
+                       << " assigned partition(s), not: " << partitions.size());
+  RdKafka::TopicPartition::destroy(partitions);
+}
+
+
+static bool TopicPartition_cmp(const RdKafka::TopicPartition *a,
+                               const RdKafka::TopicPartition *b) {
+  if (a->topic() < b->topic())
+    return true;
+  else if (a->topic() > b->topic())
+    return false;
+  return a->partition() < b->partition();
+}
+
+
+void expect_assignment(RdKafka::KafkaConsumer *consumer,
+                       vector<RdKafka::TopicPartition *> &expected) {
+  vector<RdKafka::TopicPartition *> partitions;
+  RdKafka::ErrorCode err;
+  err = consumer->assignment(partitions);
+  if (err)
+    Test::Fail(consumer->name() +
+               " assignment() failed: " + RdKafka::err2str(err));
+
+  if (partitions.size() != expected.size())
+    Test::Fail(tostr() << "Expecting consumer " << consumer->name()
+                       << " to have " << expected.size()
+                       << " assigned partition(s), not " << partitions.size());
+
+  sort(partitions.begin(), partitions.end(), TopicPartition_cmp);
+  sort(expected.begin(), expected.end(), TopicPartition_cmp);
+
+  int fails = 0;
+  for (int i = 0; i < (int)partitions.size(); i++) {
+    if (!TopicPartition_cmp(partitions[i], expected[i]))
+      continue;
+
+    Test::Say(tostr() << _C_RED << consumer->name() << ": expected assignment #"
+                      << i << " " << expected[i]->topic() << " ["
+                      << expected[i]->partition() << "], not "
+                      << partitions[i]->topic() << " ["
+                      << partitions[i]->partition() << "]\n");
+    fails++;
+  }
+
+  if (fails)
+    Test::Fail(consumer->name() + ": Expected assignment mismatch, see above");
+
+  RdKafka::TopicPartition::destroy(partitions);
+}
+
+
+class DefaultRebalanceCb : public RdKafka::RebalanceCb {
+ private:
+  static string part_list_print(
+      const vector<RdKafka::TopicPartition *> &partitions) {
+    ostringstream ss;
+    for (unsigned int i = 0; i < partitions.size(); i++)
+      ss << (i == 0 ? "" : ", ") << partitions[i]->topic() << " ["
+         << partitions[i]->partition() << "]";
+    return ss.str();
+  }
+
+ public:
+  int assign_call_cnt;
+  int revoke_call_cnt;
+  int nonempty_assign_call_cnt; /**< ASSIGN_PARTITIONS with partitions */
+  int lost_call_cnt;
+  int partitions_assigned_net;
+  bool wait_rebalance;
+  int64_t ts_last_assign;   /**< Timestamp of last rebalance assignment */
+  map<Toppar, int> msg_cnt; /**< Number of consumed messages per partition. */
+
+  ~DefaultRebalanceCb() {
+    reset_msg_cnt();
+  }
+
+  DefaultRebalanceCb() :
+      assign_call_cnt(0),
+      revoke_call_cnt(0),
+      nonempty_assign_call_cnt(0),
+      lost_call_cnt(0),
+      partitions_assigned_net(0),
+      wait_rebalance(false),
+      ts_last_assign(0) {
+  }
+
+
+  void rebalance_cb(RdKafka::KafkaConsumer *consumer,
+                    RdKafka::ErrorCode err,
+                    std::vector<RdKafka::TopicPartition *> &partitions) {
+    wait_rebalance = false;
+
+    std::string protocol = consumer->rebalance_protocol();
+
+    TEST_ASSERT(protocol == "COOPERATIVE",
+                "%s: Expected rebalance_protocol \"COOPERATIVE\", not %s",
+                consumer->name().c_str(), protocol.c_str());
+
+    const char *lost_str = consumer->assignment_lost() ? " (LOST)" : "";
+    Test::Say(tostr() << _C_YEL "RebalanceCb " << protocol << ": "
+                      << consumer->name() << " " << RdKafka::err2str(err)
+                      << lost_str << ": " << part_list_print(partitions)
+                      << "\n");
+
+    if (err == RdKafka::ERR__ASSIGN_PARTITIONS) {
+      if (consumer->assignment_lost())
+        Test::Fail("unexpected lost assignment during ASSIGN rebalance");
+      RdKafka::Error *error = consumer->incremental_assign(partitions);
+      if (error)
+        Test::Fail(tostr() << "consumer->incremental_assign() failed: "
+                           << error->str());
+      if (partitions.size() > 0)
+        nonempty_assign_call_cnt++;
+      assign_call_cnt += 1;
+      partitions_assigned_net += (int)partitions.size();
+      ts_last_assign = test_clock();
+
+    } else {
+      if (consumer->assignment_lost())
+        lost_call_cnt += 1;
+      RdKafka::Error *error = consumer->incremental_unassign(partitions);
+      if (error)
+        Test::Fail(tostr() << "consumer->incremental_unassign() failed: "
+                           << error->str());
+      if (partitions.size() == 0)
+        Test::Fail("revoked partitions size should never be 0");
+      revoke_call_cnt += 1;
+      partitions_assigned_net -= (int)partitions.size();
+    }
+
+    /* Reset message counters for the given partitions. */
+    Test::Say(consumer->name() + ": resetting message counters:\n");
+    reset_msg_cnt(partitions);
+  }
+
+  bool poll_once(RdKafka::KafkaConsumer *c, int timeout_ms) {
+    RdKafka::Message *msg = c->consume(timeout_ms);
+    bool ret              = msg->err() != RdKafka::ERR__TIMED_OUT;
+    if (!msg->err())
+      msg_cnt[Toppar(msg->topic_name(), msg->partition())]++;
+    delete msg;
+    return ret;
+  }
+
+  void reset_msg_cnt() {
+    msg_cnt.clear();
+  }
+
+  void reset_msg_cnt(Toppar &tp) {
+    int msgcnt = get_msg_cnt(tp);
+    Test::Say(tostr() << " RESET " << tp.topic << " [" << tp.partition << "]"
+                      << " with " << msgcnt << " messages\n");
+    if (!msg_cnt.erase(tp) && msgcnt)
+      Test::Fail("erase failed!");
+  }
+
+  void reset_msg_cnt(const vector<RdKafka::TopicPartition *> &partitions) {
+    for (unsigned int i = 0; i < partitions.size(); i++) {
+      Toppar tp(partitions[i]->topic(), partitions[i]->partition());
+      reset_msg_cnt(tp);
+    }
+  }
+
+  int get_msg_cnt(const Toppar &tp) {
+    map<Toppar, int>::iterator it = msg_cnt.find(tp);
+    if (it == msg_cnt.end())
+      return 0;
+    return it->second;
+  }
+};
+
+
+
+/**
+ * @brief Verify that the consumer's assignment is a subset of the
+ *        subscribed topics.
+ *
+ * @param allow_mismatch Allow assignment of not subscribed topics.
+ *                       This can happen when the subscription is updated
+ *                       but a rebalance callback hasn't been seen yet.
+ * @param all_assignments Accumulated assignments for all consumers.
+ *                        If an assigned partition already exists it means
+ *                        the partition is assigned to multiple consumers and
+ *                        the test will fail.
+ * @param exp_msg_cnt Expected message count per assigned partition, or -1
+ *                    if not to check.
+ *
+ * @returns the number of assigned partitions, or fails if the
+ *          assignment is empty or there is an assignment for
+ *          topic that is not subscribed.
+ */
+static int verify_consumer_assignment(
+    RdKafka::KafkaConsumer *consumer,
+    DefaultRebalanceCb &rebalance_cb,
+    const vector<string> &topics,
+    bool allow_empty,
+    bool allow_mismatch,
+    map<Toppar, RdKafka::KafkaConsumer *> *all_assignments,
+    int exp_msg_cnt) {
+  vector<RdKafka::TopicPartition *> partitions;
+  RdKafka::ErrorCode err;
+  int fails = 0;
+  int count;
+  ostringstream ss;
+
+  err = consumer->assignment(partitions);
+  TEST_ASSERT(!err, "Failed to get assignment for consumer %s: %s",
+              consumer->name().c_str(), RdKafka::err2str(err).c_str());
+
+  count = (int)partitions.size();
+
+  for (vector<RdKafka::TopicPartition *>::iterator it = partitions.begin();
+       it != partitions.end(); it++) {
+    RdKafka::TopicPartition *p = *it;
+
+    if (find(topics.begin(), topics.end(), p->topic()) == topics.end()) {
+      Test::Say(tostr() << (allow_mismatch ? _C_YEL "Warning (allowed)"
+                                           : _C_RED "Error")
+                        << ": " << consumer->name() << " is assigned "
+                        << p->topic() << " [" << p->partition() << "] which is "
+                        << "not in the list of subscribed topics: "
+                        << string_vec_to_str(topics) << "\n");
+      if (!allow_mismatch)
+        fails++;
+    }
+
+    Toppar tp(p);
+    pair<map<Toppar, RdKafka::KafkaConsumer *>::iterator, bool> ret;
+    ret = all_assignments->insert(
+        pair<Toppar, RdKafka::KafkaConsumer *>(tp, consumer));
+    if (!ret.second) {
+      Test::Say(tostr() << _C_RED << "Error: " << consumer->name()
+                        << " is assigned " << p->topic() << " ["
+                        << p->partition()
+                        << "] which is "
+                           "already assigned to consumer "
+                        << ret.first->second->name() << "\n");
+      fails++;
+    }
+
+
+    int msg_cnt = rebalance_cb.get_msg_cnt(tp);
+
+    if (exp_msg_cnt != -1 && msg_cnt != exp_msg_cnt) {
+      Test::Say(tostr() << _C_RED << "Error: " << consumer->name()
+                        << " expected " << exp_msg_cnt << " messages on "
+                        << p->topic() << " [" << p->partition() << "], not "
+                        << msg_cnt << "\n");
+      fails++;
+    }
+
+    ss << (it == partitions.begin() ? "" : ", ") << p->topic() << " ["
+       << p->partition() << "] (" << msg_cnt << "msgs)";
+  }
+
+  RdKafka::TopicPartition::destroy(partitions);
+
+  Test::Say(tostr() << "Consumer " << consumer->name() << " assignment ("
+                    << count << "): " << ss.str() << "\n");
+
+  if (count == 0 && !allow_empty)
+    Test::Fail("Consumer " + consumer->name() +
+               " has unexpected empty assignment");
+
+  if (fails)
+    Test::Fail(
+        tostr() << "Consumer " + consumer->name()
+                << " assignment verification failed (see previous error)");
+
+  return count;
+}
+
+
+
+/* -------- a_assign_tests
+ *
+ * check behavior incremental assign / unassign outside the context of a
+ * rebalance.
+ */
+
+
+/** Incremental assign, then assign(NULL).
+ */
+static void assign_test_1(RdKafka::KafkaConsumer *consumer,
+                          std::vector<RdKafka::TopicPartition *> toppars1,
+                          std::vector<RdKafka::TopicPartition *> toppars2) {
+  RdKafka::ErrorCode err;
+  RdKafka::Error *error;
+
+  Test::Say("Incremental assign, then assign(NULL)\n");
+
+  if ((error = consumer->incremental_assign(toppars1)))
+    Test::Fail(tostr() << "Incremental assign failed: " << error->str());
+  Test::check_assignment(consumer, 1, &toppars1[0]->topic());
+
+  if ((err = consumer->unassign()))
+    Test::Fail("Unassign failed: " + RdKafka::err2str(err));
+  Test::check_assignment(consumer, 0, NULL);
+}
+
+
+/** Assign, then incremental unassign.
+ */
+static void assign_test_2(RdKafka::KafkaConsumer *consumer,
+                          std::vector<RdKafka::TopicPartition *> toppars1,
+                          std::vector<RdKafka::TopicPartition *> toppars2) {
+  RdKafka::ErrorCode err;
+  RdKafka::Error *error;
+
+  Test::Say("Assign, then incremental unassign\n");
+
+  if ((err = consumer->assign(toppars1)))
+    Test::Fail("Assign failed: " + RdKafka::err2str(err));
+  Test::check_assignment(consumer, 1, &toppars1[0]->topic());
+
+  if ((error = consumer->incremental_unassign(toppars1)))
+    Test::Fail("Incremental unassign failed: " + error->str());
+  Test::check_assignment(consumer, 0, NULL);
+}
+
+
+/** Incremental assign, then incremental unassign.
+ */
+static void assign_test_3(RdKafka::KafkaConsumer *consumer,
+                          std::vector<RdKafka::TopicPartition *> toppars1,
+                          std::vector<RdKafka::TopicPartition *> toppars2) {
+  RdKafka::Error *error;
+
+  Test::Say("Incremental assign, then incremental unassign\n");
+
+  if ((error = consumer->incremental_assign(toppars1)))
+    Test::Fail("Incremental assign failed: " + error->str());
+  Test::check_assignment(consumer, 1, &toppars1[0]->topic());
+
+  if ((error = consumer->incremental_unassign(toppars1)))
+    Test::Fail("Incremental unassign failed: " + error->str());
+  Test::check_assignment(consumer, 0, NULL);
+}
+
+
+/** Multi-topic incremental assign and unassign + message consumption.
+ */
+static void assign_test_4(RdKafka::KafkaConsumer *consumer,
+                          std::vector<RdKafka::TopicPartition *> toppars1,
+                          std::vector<RdKafka::TopicPartition *> toppars2) {
+  RdKafka::Error *error;
+
+  Test::Say(
+      "Multi-topic incremental assign and unassign + message consumption\n");
+
+  if ((error = consumer->incremental_assign(toppars1)))
+    Test::Fail("Incremental assign failed: " + error->str());
+  Test::check_assignment(consumer, 1, &toppars1[0]->topic());
+
+  RdKafka::Message *m = consumer->consume(5000);
+  if (m->err() != RdKafka::ERR_NO_ERROR)
+    Test::Fail("Expecting a consumed message.");
+  if (m->len() != 100)
+    Test::Fail(tostr() << "Expecting msg len to be 100, not: "
+                       << m->len()); /* implies read from topic 1. */
+  delete m;
+
+  if ((error = consumer->incremental_unassign(toppars1)))
+    Test::Fail("Incremental unassign failed: " + error->str());
+  Test::check_assignment(consumer, 0, NULL);
+
+  m = consumer->consume(100);
+  if (m->err() != RdKafka::ERR__TIMED_OUT)
+    Test::Fail("Not expecting a consumed message.");
+  delete m;
+
+  if ((error = consumer->incremental_assign(toppars2)))
+    Test::Fail("Incremental assign failed: " + error->str());
+  Test::check_assignment(consumer, 1, &toppars2[0]->topic());
+
+  m = consumer->consume(5000);
+  if (m->err() != RdKafka::ERR_NO_ERROR)
+    Test::Fail("Expecting a consumed message.");
+  if (m->len() != 200)
+    Test::Fail(tostr() << "Expecting msg len to be 200, not: "
+                       << m->len()); /* implies read from topic 2. */
+  delete m;
+
+  if ((error = consumer->incremental_assign(toppars1)))
+    Test::Fail("Incremental assign failed: " + error->str());
+  if (Test::assignment_partition_count(consumer, NULL) != 2)
+    Test::Fail(tostr() << "Expecting current assignment to have size 2, not: "
+                       << Test::assignment_partition_count(consumer, NULL));
+
+  m = consumer->consume(5000);
+  if (m->err() != RdKafka::ERR_NO_ERROR)
+    Test::Fail("Expecting a consumed message.");
+  delete m;
+
+  if ((error = consumer->incremental_unassign(toppars2)))
+    Test::Fail("Incremental unassign failed: " + error->str());
+  if ((error = consumer->incremental_unassign(toppars1)))
+    Test::Fail("Incremental unassign failed: " + error->str());
+  Test::check_assignment(consumer, 0, NULL);
+}
+
+
+/** Incremental assign and unassign of empty collection.
+ */
+static void assign_test_5(RdKafka::KafkaConsumer *consumer,
+                          std::vector<RdKafka::TopicPartition *> toppars1,
+                          std::vector<RdKafka::TopicPartition *> toppars2) {
+  RdKafka::Error *error;
+  std::vector<RdKafka::TopicPartition *> toppars3;
+
+  Test::Say("Incremental assign and unassign of empty collection\n");
+
+  if ((error = consumer->incremental_assign(toppars3)))
+    Test::Fail("Incremental assign failed: " + error->str());
+  Test::check_assignment(consumer, 0, NULL);
+
+  if ((error = consumer->incremental_unassign(toppars3)))
+    Test::Fail("Incremental unassign failed: " + error->str());
+  Test::check_assignment(consumer, 0, NULL);
+}
+
+
+
+static void run_test(
+    const std::string &t1,
+    const std::string &t2,
+    void (*test)(RdKafka::KafkaConsumer *consumer,
+                 std::vector<RdKafka::TopicPartition *> toppars1,
+                 std::vector<RdKafka::TopicPartition *> toppars2)) {
+  std::vector<RdKafka::TopicPartition *> toppars1;
+  toppars1.push_back(RdKafka::TopicPartition::create(t1, 0));
+  std::vector<RdKafka::TopicPartition *> toppars2;
+  toppars2.push_back(RdKafka::TopicPartition::create(t2, 0));
+
+  RdKafka::KafkaConsumer *consumer =
+      make_consumer("C_1", t1, "cooperative-sticky", NULL, NULL, 10);
+
+  test(consumer, toppars1, toppars2);
+
+  RdKafka::TopicPartition::destroy(toppars1);
+  RdKafka::TopicPartition::destroy(toppars2);
+
+  consumer->close();
+  delete consumer;
+}
+
+
+static void a_assign_tests() {
+  SUB_TEST_QUICK();
+
+  int msgcnt         = 1000;
+  const int msgsize1 = 100;
+  const int msgsize2 = 200;
+
+  std::string topic1_str = Test::mk_topic_name("0113-a1", 1);
+  test_create_topic(NULL, topic1_str.c_str(), 1, 1);
+  std::string topic2_str = Test::mk_topic_name("0113-a2", 1);
+  test_create_topic(NULL, topic2_str.c_str(), 1, 1);
+
+  test_produce_msgs_easy_size(topic1_str.c_str(), 0, 0, msgcnt, msgsize1);
+  test_produce_msgs_easy_size(topic2_str.c_str(), 0, 0, msgcnt, msgsize2);
+
+  run_test(topic1_str, topic2_str, assign_test_1);
+  run_test(topic1_str, topic2_str, assign_test_2);
+  run_test(topic1_str, topic2_str, assign_test_3);
+  run_test(topic1_str, topic2_str, assign_test_4);
+  run_test(topic1_str, topic2_str, assign_test_5);
+
+  SUB_TEST_PASS();
+}
+
+
+
+/**
+ * @brief Quick Assign 1,2, Assign 2,3, Assign 1,2,3 test to verify
+ *        that the correct OffsetFetch response is used.
+ *        See note in rdkafka_assignment.c for details.
+ *
+ * Makes use of the mock cluster to induce latency.
+ */
+static void a_assign_rapid() {
+  SUB_TEST_QUICK();
+
+  std::string group_id = __FUNCTION__;
+
+  rd_kafka_mock_cluster_t *mcluster;
+  const char *bootstraps;
+
+  mcluster         = test_mock_cluster_new(3, &bootstraps);
+  int32_t coord_id = 1;
+  rd_kafka_mock_coordinator_set(mcluster, "group", group_id.c_str(), coord_id);
+
+  rd_kafka_mock_topic_create(mcluster, "topic1", 1, 1);
+  rd_kafka_mock_topic_create(mcluster, "topic2", 1, 1);
+  rd_kafka_mock_topic_create(mcluster, "topic3", 1, 1);
+
+  /*
+   * Produce messages to topics
+   */
+  const int msgs_per_partition = 1000;
+
+  RdKafka::Conf *pconf;
+  Test::conf_init(&pconf, NULL, 10);
+  Test::conf_set(pconf, "bootstrap.servers", bootstraps);
+  Test::conf_set(pconf, "security.protocol", "plaintext");
+  std::string errstr;
+  RdKafka::Producer *p = RdKafka::Producer::create(pconf, errstr);
+  if (!p)
+    Test::Fail(tostr() << __FUNCTION__
+                       << ": Failed to create producer: " << errstr);
+  delete pconf;
+
+  Test::produce_msgs(p, "topic1", 0, msgs_per_partition, 10,
+                     false /*no flush*/);
+  Test::produce_msgs(p, "topic2", 0, msgs_per_partition, 10,
+                     false /*no flush*/);
+  Test::produce_msgs(p, "topic3", 0, msgs_per_partition, 10,
+                     false /*no flush*/);
+  p->flush(10 * 1000);
+
+  delete p;
+
+  vector<RdKafka::TopicPartition *> toppars1;
+  toppars1.push_back(RdKafka::TopicPartition::create("topic1", 0));
+  vector<RdKafka::TopicPartition *> toppars2;
+  toppars2.push_back(RdKafka::TopicPartition::create("topic2", 0));
+  vector<RdKafka::TopicPartition *> toppars3;
+  toppars3.push_back(RdKafka::TopicPartition::create("topic3", 0));
+
+
+  RdKafka::Conf *conf;
+  Test::conf_init(&conf, NULL, 20);
+  Test::conf_set(conf, "bootstrap.servers", bootstraps);
+  Test::conf_set(conf, "security.protocol", "plaintext");
+  Test::conf_set(conf, "client.id", __FUNCTION__);
+  Test::conf_set(conf, "group.id", group_id);
+  Test::conf_set(conf, "auto.offset.reset", "earliest");
+  Test::conf_set(conf, "enable.auto.commit", "false");
+
+  RdKafka::KafkaConsumer *consumer;
+  consumer = RdKafka::KafkaConsumer::create(conf, errstr);
+  if (!consumer)
+    Test::Fail(tostr() << __FUNCTION__
+                       << ": Failed to create consumer: " << errstr);
+  delete conf;
+
+  vector<RdKafka::TopicPartition *> toppars;
+  vector<RdKafka::TopicPartition *> expected;
+
+  map<Toppar, int64_t> pos; /* Expected consume position per partition */
+  pos[Toppar(toppars1[0]->topic(), toppars1[0]->partition())] = 0;
+  pos[Toppar(toppars2[0]->topic(), toppars2[0]->partition())] = 0;
+  pos[Toppar(toppars3[0]->topic(), toppars3[0]->partition())] = 0;
+
+  /* To make sure offset commits are fetched in proper assign sequence
+   * we commit an offset that should not be used in the final consume loop.
+   * This commit will be overwritten below with another commit. */
+  vector<RdKafka::TopicPartition *> offsets;
+  offsets.push_back(RdKafka::TopicPartition::create(
+      toppars1[0]->topic(), toppars1[0]->partition(), 11));
+  /* This partition should start at this position even though
+   * there will be a sub-sequent commit to overwrite it, that should not
+   * be used since this partition is never unassigned. */
+  offsets.push_back(RdKafka::TopicPartition::create(
+      toppars2[0]->topic(), toppars2[0]->partition(), 22));
+  pos[Toppar(toppars2[0]->topic(), toppars2[0]->partition())] = 22;
+
+  Test::print_TopicPartitions("pre-commit", offsets);
+
+  RdKafka::ErrorCode err;
+  err = consumer->commitSync(offsets);
+  if (err)
+    Test::Fail(tostr() << __FUNCTION__ << ": pre-commit failed: "
+                       << RdKafka::err2str(err) << "\n");
+
+  /* Add coordinator delay so that the OffsetFetchRequest originating
+   * from the coming incremental_assign() will not finish before
+   * we call incremental_unassign() and incremental_assign() again, resulting
+   * in a situation where the initial OffsetFetchResponse will contain
+   * an older offset for a previous assignment of one partition. */
+  rd_kafka_mock_broker_set_rtt(mcluster, coord_id, 5000);
+
+
+  /* Assign 1,2 == 1,2 */
+  toppars.push_back(toppars1[0]);
+  toppars.push_back(toppars2[0]);
+  expected.push_back(toppars1[0]);
+  expected.push_back(toppars2[0]);
+  Test::incremental_assign(consumer, toppars);
+  expect_assignment(consumer, expected);
+
+  /* Unassign -1 == 2 */
+  toppars.clear();
+  toppars.push_back(toppars1[0]);
+  vector<RdKafka::TopicPartition *>::iterator it =
+      find(expected.begin(), expected.end(), toppars1[0]);
+  expected.erase(it);
+
+  Test::incremental_unassign(consumer, toppars);
+  expect_assignment(consumer, expected);
+
+
+  /* Commit offset for the removed partition and the partition that is
+   * unchanged in the assignment. */
+  RdKafka::TopicPartition::destroy(offsets);
+  offsets.push_back(RdKafka::TopicPartition::create(
+      toppars1[0]->topic(), toppars1[0]->partition(), 55));
+  offsets.push_back(RdKafka::TopicPartition::create(
+      toppars2[0]->topic(), toppars2[0]->partition(), 33)); /* should not be
+                                                             * used. */
+  pos[Toppar(toppars1[0]->topic(), toppars1[0]->partition())] = 55;
+  Test::print_TopicPartitions("commit", offsets);
+
+  err = consumer->commitAsync(offsets);
+  if (err)
+    Test::Fail(tostr() << __FUNCTION__
+                       << ": commit failed: " << RdKafka::err2str(err) << "\n");
+
+  /* Assign +3 == 2,3 */
+  toppars.clear();
+  toppars.push_back(toppars3[0]);
+  expected.push_back(toppars3[0]);
+  Test::incremental_assign(consumer, toppars);
+  expect_assignment(consumer, expected);
+
+  /* Now remove the latency */
+  Test::Say(_C_MAG "Clearing rtt\n");
+  rd_kafka_mock_broker_set_rtt(mcluster, coord_id, 0);
+
+  /* Assign +1 == 1,2,3 */
+  toppars.clear();
+  toppars.push_back(toppars1[0]);
+  expected.push_back(toppars1[0]);
+  Test::incremental_assign(consumer, toppars);
+  expect_assignment(consumer, expected);
+
+  /*
+   * Verify consumed messages
+   */
+  int wait_end = (int)expected.size();
+  while (wait_end > 0) {
+    RdKafka::Message *msg = consumer->consume(10 * 1000);
+    if (msg->err() == RdKafka::ERR__TIMED_OUT)
+      Test::Fail(tostr() << __FUNCTION__
+                         << ": Consume timed out waiting "
+                            "for "
+                         << wait_end << " more partitions");
+
+    Toppar tp        = Toppar(msg->topic_name(), msg->partition());
+    int64_t *exp_pos = &pos[tp];
+
+    Test::Say(3, tostr() << __FUNCTION__ << ": Received " << tp.topic << " ["
+                         << tp.partition << "] at offset " << msg->offset()
+                         << " (expected offset " << *exp_pos << ")\n");
+
+    if (*exp_pos != msg->offset())
+      Test::Fail(tostr() << __FUNCTION__ << ": expected message offset "
+                         << *exp_pos << " for " << msg->topic_name() << " ["
+                         << msg->partition() << "], not " << msg->offset()
+                         << "\n");
+    (*exp_pos)++;
+    if (*exp_pos == msgs_per_partition) {
+      TEST_ASSERT(wait_end > 0, "");
+      wait_end--;
+    } else if (msg->offset() > msgs_per_partition)
+      Test::Fail(tostr() << __FUNCTION__ << ": unexpected message with "
+                         << "offset " << msg->offset() << " on " << tp.topic
+                         << " [" << tp.partition << "]\n");
+
+    delete msg;
+  }
+
+  RdKafka::TopicPartition::destroy(offsets);
+  RdKafka::TopicPartition::destroy(toppars1);
+  RdKafka::TopicPartition::destroy(toppars2);
+  RdKafka::TopicPartition::destroy(toppars3);
+
+  delete consumer;
+
+  test_mock_cluster_destroy(mcluster);
+
+  SUB_TEST_PASS();
+}
+
+
+/* Check behavior when:
+ *   1. single topic with 2 partitions.
+ *   2. consumer 1 (with rebalance_cb) subscribes to it.
+ *   3. consumer 2 (with rebalance_cb) subscribes to it.
+ *   4. close.
+ */
+
+static void b_subscribe_with_cb_test(rd_bool_t close_consumer) {
+  SUB_TEST();
+
+  std::string topic_name = Test::mk_topic_name("0113-cooperative_rebalance", 1);
+  std::string group_name =
+      Test::mk_unique_group_name("0113-cooperative_rebalance");
+  test_create_topic(NULL, topic_name.c_str(), 2, 1);
+
+  DefaultRebalanceCb rebalance_cb1;
+  RdKafka::KafkaConsumer *c1 = make_consumer(
+      "C_1", group_name, "cooperative-sticky", NULL, &rebalance_cb1, 25);
+  DefaultRebalanceCb rebalance_cb2;
+  RdKafka::KafkaConsumer *c2 = make_consumer(
+      "C_2", group_name, "cooperative-sticky", NULL, &rebalance_cb2, 25);
+  test_wait_topic_exists(c1->c_ptr(), topic_name.c_str(), 10 * 1000);
+
+  Test::subscribe(c1, topic_name);
+
+  bool c2_subscribed = false;
+  while (true) {
+    Test::poll_once(c1, 500);
+    Test::poll_once(c2, 500);
+
+    /* Start c2 after c1 has received initial assignment */
+    if (!c2_subscribed && rebalance_cb1.assign_call_cnt > 0) {
+      Test::subscribe(c2, topic_name);
+      c2_subscribed = true;
+    }
+
+    /* Failure case: test will time out. */
+    if (rebalance_cb1.assign_call_cnt == 3 &&
+        rebalance_cb2.assign_call_cnt == 2) {
+      break;
+    }
+  }
+
+  /* Sequence of events:
+   *
+   * 1. c1 joins group.
+   * 2. c1 gets assigned 2 partitions.
+   *     - there isn't a follow-on rebalance because there aren't any revoked
+   * partitions.
+   * 3. c2 joins group.
+   * 4. This results in a rebalance with one partition being revoked from c1,
+   * and no partitions assigned to either c1 or c2 (however the rebalance
+   * callback will be called in each case with an empty set).
+   * 5. c1 then re-joins the group since it had a partition revoked.
+   * 6. c2 is now assigned a single partition, and c1's incremental assignment
+   * is empty.
+   * 7. Since there were no revoked partitions, no further rebalance is
+   * triggered.
+   */
+
+  /* The rebalance cb is always called on assign, even if empty. */
+  if (rebalance_cb1.assign_call_cnt != 3)
+    Test::Fail(tostr() << "Expecting 3 assign calls on consumer 1, not "
+                       << rebalance_cb1.assign_call_cnt);
+  if (rebalance_cb2.assign_call_cnt != 2)
+    Test::Fail(tostr() << "Expecting 2 assign calls on consumer 2, not: "
+                       << rebalance_cb2.assign_call_cnt);
+
+  /* The rebalance cb is not called on and empty revoke (unless partitions lost,
+   * which is not the case here) */
+  if (rebalance_cb1.revoke_call_cnt != 1)
+    Test::Fail(tostr() << "Expecting 1 revoke call on consumer 1, not: "
+                       << rebalance_cb1.revoke_call_cnt);
+  if (rebalance_cb2.revoke_call_cnt != 0)
+    Test::Fail(tostr() << "Expecting 0 revoke calls on consumer 2, not: "
+                       << rebalance_cb2.revoke_call_cnt);
+
+  /* Final state */
+
+  /* Expect both consumers to have 1 assigned partition (via net calculation in
+   * rebalance_cb) */
+  if (rebalance_cb1.partitions_assigned_net != 1)
+    Test::Fail(tostr()
+               << "Expecting consumer 1 to have net 1 assigned partition, not: "
+               << rebalance_cb1.partitions_assigned_net);
+  if (rebalance_cb2.partitions_assigned_net != 1)
+    Test::Fail(tostr()
+               << "Expecting consumer 2 to have net 1 assigned partition, not: "
+               << rebalance_cb2.partitions_assigned_net);
+
+  /* Expect both consumers to have 1 assigned partition (via ->assignment()
+   * query) */
+  expect_assignment(c1, 1);
+  expect_assignment(c2, 1);
+
+  /* Make sure the fetchers are running */
+  int msgcnt         = 100;
+  const int msgsize1 = 100;
+  test_produce_msgs_easy_size(topic_name.c_str(), 0, 0, msgcnt, msgsize1);
+  test_produce_msgs_easy_size(topic_name.c_str(), 0, 1, msgcnt, msgsize1);
+
+  bool consumed_from_c1 = false;
+  bool consumed_from_c2 = false;
+  while (true) {
+    RdKafka::Message *msg1 = c1->consume(100);
+    RdKafka::Message *msg2 = c2->consume(100);
+
+    if (msg1->err() == RdKafka::ERR_NO_ERROR)
+      consumed_from_c1 = true;
+    if (msg1->err() == RdKafka::ERR_NO_ERROR)
+      consumed_from_c2 = true;
+
+    delete msg1;
+    delete msg2;
+
+    /* Failure case: test will timeout. */
+    if (consumed_from_c1 && consumed_from_c2)
+      break;
+  }
+
+  if (!close_consumer) {
+    delete c1;
+    delete c2;
+    return;
+  }
+
+  c1->close();
+  c2->close();
+
+  /* Closing the consumer should trigger rebalance_cb (revoke): */
+  if (rebalance_cb1.revoke_call_cnt != 2)
+    Test::Fail(tostr() << "Expecting 2 revoke calls on consumer 1, not: "
+                       << rebalance_cb1.revoke_call_cnt);
+  if (rebalance_cb2.revoke_call_cnt != 1)
+    Test::Fail(tostr() << "Expecting 1 revoke call on consumer 2, not: "
+                       << rebalance_cb2.revoke_call_cnt);
+
+  /* ..and net assigned partitions should drop to 0 in both cases: */
+  if (rebalance_cb1.partitions_assigned_net != 0)
+    Test::Fail(
+        tostr()
+        << "Expecting consumer 1 to have net 0 assigned partitions, not: "
+        << rebalance_cb1.partitions_assigned_net);
+  if (rebalance_cb2.partitions_assigned_net != 0)
+    Test::Fail(
+        tostr()
+        << "Expecting consumer 2 to have net 0 assigned partitions, not: "
+        << rebalance_cb2.partitions_assigned_net);
+
+  /* Nothing in this test should result in lost partitions */
+  if (rebalance_cb1.lost_call_cnt > 0)
+    Test::Fail(
+        tostr() << "Expecting consumer 1 to have 0 lost partition events, not: "
+                << rebalance_cb1.lost_call_cnt);
+  if (rebalance_cb2.lost_call_cnt > 0)
+    Test::Fail(
+        tostr() << "Expecting consumer 2 to have 0 lost partition events, not: "
+                << rebalance_cb2.lost_call_cnt);
+
+  delete c1;
+  delete c2;
+
+  SUB_TEST_PASS();
+}
+
+
+
+/* Check behavior when:
+ *   1. Single topic with 2 partitions.
+ *   2. Consumer 1 (no rebalance_cb) subscribes to it.
+ *   3. Consumer 2 (no rebalance_cb) subscribes to it.
+ *   4. Close.
+ */
+
+static void c_subscribe_no_cb_test(rd_bool_t close_consumer) {
+  SUB_TEST();
+
+  std::string topic_name = Test::mk_topic_name("0113-cooperative_rebalance", 1);
+  std::string group_name =
+      Test::mk_unique_group_name("0113-cooperative_rebalance");
+  test_create_topic(NULL, topic_name.c_str(), 2, 1);
+
+  RdKafka::KafkaConsumer *c1 =
+      make_consumer("C_1", group_name, "cooperative-sticky", NULL, NULL, 20);
+  RdKafka::KafkaConsumer *c2 =
+      make_consumer("C_2", group_name, "cooperative-sticky", NULL, NULL, 20);
+  test_wait_topic_exists(c1->c_ptr(), topic_name.c_str(), 10 * 1000);
+
+  Test::subscribe(c1, topic_name);
+
+  bool c2_subscribed = false;
+  bool done          = false;
+  while (!done) {
+    Test::poll_once(c1, 500);
+    Test::poll_once(c2, 500);
+
+    if (Test::assignment_partition_count(c1, NULL) == 2 && !c2_subscribed) {
+      Test::subscribe(c2, topic_name);
+      c2_subscribed = true;
+    }
+
+    if (Test::assignment_partition_count(c1, NULL) == 1 &&
+        Test::assignment_partition_count(c2, NULL) == 1) {
+      Test::Say("Consumer 1 and 2 are both assigned to single partition.\n");
+      done = true;
+    }
+  }
+
+  if (close_consumer) {
+    Test::Say("Closing consumer 1\n");
+    c1->close();
+    Test::Say("Closing consumer 2\n");
+    c2->close();
+  } else {
+    Test::Say("Skipping close() of consumer 1 and 2.\n");
+  }
+
+  delete c1;
+  delete c2;
+
+  SUB_TEST_PASS();
+}
+
+
+
+/* Check behavior when:
+ *   1. Single consumer (no rebalance_cb) subscribes to topic.
+ *   2. Subscription is changed (topic added).
+ *   3. Consumer is closed.
+ */
+
+static void d_change_subscription_add_topic(rd_bool_t close_consumer) {
+  SUB_TEST();
+
+  std::string topic_name_1 =
+      Test::mk_topic_name("0113-cooperative_rebalance", 1);
+  test_create_topic(NULL, topic_name_1.c_str(), 2, 1);
+  std::string topic_name_2 =
+      Test::mk_topic_name("0113-cooperative_rebalance", 1);
+  test_create_topic(NULL, topic_name_2.c_str(), 2, 1);
+
+  std::string group_name =
+      Test::mk_unique_group_name("0113-cooperative_rebalance");
+
+  RdKafka::KafkaConsumer *c =
+      make_consumer("C_1", group_name, "cooperative-sticky", NULL, NULL, 15);
+  test_wait_topic_exists(c->c_ptr(), topic_name_1.c_str(), 10 * 1000);
+  test_wait_topic_exists(c->c_ptr(), topic_name_2.c_str(), 10 * 1000);
+
+  Test::subscribe(c, topic_name_1);
+
+  bool subscribed_to_one_topic = false;
+  bool done                    = false;
+  while (!done) {
+    Test::poll_once(c, 500);
+
+    if (Test::assignment_partition_count(c, NULL) == 2 &&
+        !subscribed_to_one_topic) {
+      subscribed_to_one_topic = true;
+      Test::subscribe(c, topic_name_1, topic_name_2);
+    }
+
+    if (Test::assignment_partition_count(c, NULL) == 4) {
+      Test::Say("Consumer is assigned to two topics.\n");
+      done = true;
+    }
+  }
+
+  if (close_consumer) {
+    Test::Say("Closing consumer\n");
+    c->close();
+  } else
+    Test::Say("Skipping close() of consumer\n");
+
+  delete c;
+
+  SUB_TEST_PASS();
+}
+
+
+
+/* Check behavior when:
+ *   1. Single consumer (no rebalance_cb) subscribes to topic.
+ *   2. Subscription is changed (topic added).
+ *   3. Consumer is closed.
+ */
+
+static void e_change_subscription_remove_topic(rd_bool_t close_consumer) {
+  SUB_TEST();
+
+  std::string topic_name_1 =
+      Test::mk_topic_name("0113-cooperative_rebalance", 1);
+  test_create_topic(NULL, topic_name_1.c_str(), 2, 1);
+  std::string topic_name_2 =
+      Test::mk_topic_name("0113-cooperative_rebalance", 1);
+  test_create_topic(NULL, topic_name_2.c_str(), 2, 1);
+
+  std::string group_name =
+      Test::mk_unique_group_name("0113-cooperative_rebalance");
+
+  RdKafka::KafkaConsumer *c =
+      make_consumer("C_1", group_name, "cooperative-sticky", NULL, NULL, 15);
+  test_wait_topic_exists(c->c_ptr(), topic_name_1.c_str(), 10 * 1000);
+  test_wait_topic_exists(c->c_ptr(), topic_name_2.c_str(), 10 * 1000);
+
+  Test::subscribe(c, topic_name_1, topic_name_2);
+
+  bool subscribed_to_two_topics = false;
+  bool done                     = false;
+  while (!done) {
+    Test::poll_once(c, 500);
+
+    if (Test::assignment_partition_count(c, NULL) == 4 &&
+        !subscribed_to_two_topics) {
+      subscribed_to_two_topics = true;
+      Test::subscribe(c, topic_name_1);
+    }
+
+    if (Test::assignment_partition_count(c, NULL) == 2) {
+      Test::Say("Consumer is assigned to one topic\n");
+      done = true;
+    }
+  }
+
+  if (!close_consumer) {
+    Test::Say("Closing consumer\n");
+    c->close();
+  } else
+    Test::Say("Skipping close() of consumer\n");
+
+  delete c;
+
+  SUB_TEST_PASS();
+}
+
+
+
+/* Check that use of consumer->assign() and consumer->unassign() is disallowed
+ * when a COOPERATIVE assignor is in use.
+ *
+ * Except when the consumer is closing, where all forms of unassign are
+ * allowed and treated as a full unassign.
+ */
+
+class FTestRebalanceCb : public RdKafka::RebalanceCb {
+ public:
+  bool assigned;
+  bool closing;
+
+  FTestRebalanceCb() : assigned(false), closing(false) {
+  }
+
+  void rebalance_cb(RdKafka::KafkaConsumer *consumer,
+                    RdKafka::ErrorCode err,
+                    std::vector<RdKafka::TopicPartition *> &partitions) {
+    Test::Say(tostr() << "RebalanceCb: " << consumer->name() << " "
+                      << RdKafka::err2str(err) << (closing ? " (closing)" : "")
+                      << "\n");
+
+    if (err == RdKafka::ERR__ASSIGN_PARTITIONS) {
+      RdKafka::ErrorCode err_resp = consumer->assign(partitions);
+      Test::Say(tostr() << "consumer->assign() response code: " << err_resp
+                        << "\n");
+      if (err_resp != RdKafka::ERR__STATE)
+        Test::Fail(tostr() << "Expected assign to fail with error code: "
+                           << RdKafka::ERR__STATE << "(ERR__STATE)");
+
+      RdKafka::Error *error = consumer->incremental_assign(partitions);
+      if (error)
+        Test::Fail(tostr() << "consumer->incremental_unassign() failed: "
+                           << error->str());
+
+      assigned = true;
+
+    } else {
+      RdKafka::ErrorCode err_resp = consumer->unassign();
+      Test::Say(tostr() << "consumer->unassign() response code: " << err_resp
+                        << "\n");
+
+      if (!closing) {
+        if (err_resp != RdKafka::ERR__STATE)
+          Test::Fail(tostr() << "Expected assign to fail with error code: "
+                             << RdKafka::ERR__STATE << "(ERR__STATE)");
+
+        RdKafka::Error *error = consumer->incremental_unassign(partitions);
+        if (error)
+          Test::Fail(tostr() << "consumer->incremental_unassign() failed: "
+                             << error->str());
+
+      } else {
+        /* During termination (close()) any type of unassign*() is allowed. */
+        if (err_resp)
+          Test::Fail(tostr() << "Expected unassign to succeed during close, "
+                                "but got: "
+                             << RdKafka::ERR__STATE << "(ERR__STATE)");
+      }
+    }
+  }
+};
+
+
+static void f_assign_call_cooperative() {
+  SUB_TEST();
+
+  std::string topic_name = Test::mk_topic_name("0113-cooperative_rebalance", 1);
+  test_create_topic(NULL, topic_name.c_str(), 1, 1);
+
+  std::string group_name =
+      Test::mk_unique_group_name("0113-cooperative_rebalance");
+
+  std::vector<std::pair<std::string, std::string> > additional_conf;
+  additional_conf.push_back(std::pair<std::string, std::string>(
+      std::string("topic.metadata.refresh.interval.ms"), std::string("3000")));
+  FTestRebalanceCb rebalance_cb;
+  RdKafka::KafkaConsumer *c =
+      make_consumer("C_1", group_name, "cooperative-sticky", &additional_conf,
+                    &rebalance_cb, 15);
+  test_wait_topic_exists(c->c_ptr(), topic_name.c_str(), 10 * 1000);
+
+  Test::subscribe(c, topic_name);
+
+  while (!rebalance_cb.assigned)
+    Test::poll_once(c, 500);
+
+  rebalance_cb.closing = true;
+  c->close();
+  delete c;
+
+  SUB_TEST_PASS();
+}
+
+
+
+/* Check that use of consumer->incremental_assign() and
+ * consumer->incremental_unassign() is disallowed when an EAGER assignor is in
+ * use.
+ */
+class GTestRebalanceCb : public RdKafka::RebalanceCb {
+ public:
+  bool assigned;
+  bool closing;
+
+  GTestRebalanceCb() : assigned(false), closing(false) {
+  }
+
+  void rebalance_cb(RdKafka::KafkaConsumer *consumer,
+                    RdKafka::ErrorCode err,
+                    std::vector<RdKafka::TopicPartition *> &partitions) {
+    Test::Say(tostr() << "RebalanceCb: " << consumer->name() << " "
+                      << RdKafka::err2str(err) << "\n");
+
+    if (err == RdKafka::ERR__ASSIGN_PARTITIONS) {
+      RdKafka::Error *error = consumer->incremental_assign(partitions);
+      Test::Say(tostr() << "consumer->incremental_assign() response: "
+                        << (!error ? "NULL" : error->str()) << "\n");
+      if (!error)
+        Test::Fail("Expected consumer->incremental_assign() to fail");
+      if (error->code() != RdKafka::ERR__STATE)
+        Test::Fail(tostr() << "Expected consumer->incremental_assign() to fail "
+                              "with error code "
+                           << RdKafka::ERR__STATE);
+      delete error;
+
+      RdKafka::ErrorCode err_resp = consumer->assign(partitions);
+      if (err_resp)
+        Test::Fail(tostr() << "consumer->assign() failed: " << err_resp);
+
+      assigned = true;
+
+    } else {
+      RdKafka::Error *error = consumer->incremental_unassign(partitions);
+      Test::Say(tostr() << "consumer->incremental_unassign() response: "
+                        << (!error ? "NULL" : error->str()) << "\n");
+
+      if (!closing) {
+        if (!error)
+          Test::Fail("Expected consumer->incremental_unassign() to fail");
+        if (error->code() != RdKafka::ERR__STATE)
+          Test::Fail(tostr() << "Expected consumer->incremental_unassign() to "
+                                "fail with error code "
+                             << RdKafka::ERR__STATE);
+        delete error;
+
+        RdKafka::ErrorCode err_resp = consumer->unassign();
+        if (err_resp)
+          Test::Fail(tostr() << "consumer->unassign() failed: " << err_resp);
+
+      } else {
+        /* During termination (close()) any type of unassign*() is allowed. */
+        if (error)
+          Test::Fail(
+              tostr()
+              << "Expected incremental_unassign to succeed during close, "
+                 "but got: "
+              << RdKafka::ERR__STATE << "(ERR__STATE)");
+      }
+    }
+  }
+};
+
+static void g_incremental_assign_call_eager() {
+  SUB_TEST();
+
+  std::string topic_name = Test::mk_topic_name("0113-cooperative_rebalance", 1);
+  test_create_topic(NULL, topic_name.c_str(), 1, 1);
+
+  std::string group_name =
+      Test::mk_unique_group_name("0113-cooperative_rebalance");
+
+  std::vector<std::pair<std::string, std::string> > additional_conf;
+  additional_conf.push_back(std::pair<std::string, std::string>(
+      std::string("topic.metadata.refresh.interval.ms"), std::string("3000")));
+  GTestRebalanceCb rebalance_cb;
+  RdKafka::KafkaConsumer *c = make_consumer(
+      "C_1", group_name, "roundrobin", &additional_conf, &rebalance_cb, 15);
+  test_wait_topic_exists(c->c_ptr(), topic_name.c_str(), 10 * 1000);
+
+  Test::subscribe(c, topic_name);
+
+  while (!rebalance_cb.assigned)
+    Test::poll_once(c, 500);
+
+  rebalance_cb.closing = true;
+  c->close();
+  delete c;
+
+  SUB_TEST_PASS();
+}
+
+
+
+/* Check behavior when:
+ *   1. Single consumer (rebalance_cb) subscribes to two topics.
+ *   2. One of the topics is deleted.
+ *   3. Consumer is closed.
+ */
+
+static void h_delete_topic() {
+  SUB_TEST();
+
+  std::string topic_name_1 =
+      Test::mk_topic_name("0113-cooperative_rebalance", 1);
+  test_create_topic(NULL, topic_name_1.c_str(), 1, 1);
+  std::string topic_name_2 =
+      Test::mk_topic_name("0113-cooperative_rebalance", 1);
+  test_create_topic(NULL, topic_name_2.c_str(), 1, 1);
+
+  std::string group_name =
+      Test::mk_unique_group_name("0113-cooperative_rebalance");
+
+  std::vector<std::pair<std::string, std::string> > additional_conf;
+  additional_conf.push_back(std::pair<std::string, std::string>(
+      std::string("topic.metadata.refresh.interval.ms"), std::string("3000")));
+  DefaultRebalanceCb rebalance_cb;
+  RdKafka::KafkaConsumer *c =
+      make_consumer("C_1", group_name, "cooperative-sticky", &additional_conf,
+                    &rebalance_cb, 15);
+  test_wait_topic_exists(c->c_ptr(), topic_name_1.c_str(), 10 * 1000);
+  test_wait_topic_exists(c->c_ptr(), topic_name_2.c_str(), 10 * 1000);
+
+  Test::subscribe(c, topic_name_1, topic_name_2);
+
+  bool deleted = false;
+  bool done    = false;
+  while (!done) {
+    Test::poll_once(c, 500);
+
+    std::vector<RdKafka::TopicPartition *> partitions;
+    c->assignment(partitions);
+
+    if (partitions.size() == 2 && !deleted) {
+      if (rebalance_cb.assign_call_cnt != 1)
+        Test::Fail(tostr() << "Expected 1 assign call, saw "
+                           << rebalance_cb.assign_call_cnt << "\n");
+      Test::delete_topic(c, topic_name_2.c_str());
+      deleted = true;
+    }
+
+    if (partitions.size() == 1 && deleted) {
+      if (partitions[0]->topic() != topic_name_1)
+        Test::Fail(tostr() << "Expecting subscribed topic to be '"
+                           << topic_name_1 << "' not '"
+                           << partitions[0]->topic() << "'");
+      Test::Say(tostr() << "Assignment no longer includes deleted topic '"
+                        << topic_name_2 << "'\n");
+      done = true;
+    }
+
+    RdKafka::TopicPartition::destroy(partitions);
+  }
+
+  Test::Say("Closing consumer\n");
+  c->close();
+
+  delete c;
+
+  SUB_TEST_PASS();
+}
+
+
+
+/* Check behavior when:
+ *   1. Single consumer (rebalance_cb) subscribes to a single topic.
+ *   2. That topic is deleted leaving no topics.
+ *   3. Consumer is closed.
+ */
+
+static void i_delete_topic_2() {
+  SUB_TEST();
+
+  std::string topic_name_1 =
+      Test::mk_topic_name("0113-cooperative_rebalance", 1);
+  test_create_topic(NULL, topic_name_1.c_str(), 1, 1);
+  std::string group_name =
+      Test::mk_unique_group_name("0113-cooperative_rebalance");
+
+  std::vector<std::pair<std::string, std::string> > additional_conf;
+  additional_conf.push_back(std::pair<std::string, std::string>(
+      std::string("topic.metadata.refresh.interval.ms"), std::string("3000")));
+  DefaultRebalanceCb rebalance_cb;
+  RdKafka::KafkaConsumer *c =
+      make_consumer("C_1", group_name, "cooperative-sticky", &additional_conf,
+                    &rebalance_cb, 15);
+  test_wait_topic_exists(c->c_ptr(), topic_name_1.c_str(), 10 * 1000);
+
+  Test::subscribe(c, topic_name_1);
+
+  bool deleted = false;
+  bool done    = false;
+  while (!done) {
+    Test::poll_once(c, 500);
+
+    if (Test::assignment_partition_count(c, NULL) == 1 && !deleted) {
+      if (rebalance_cb.assign_call_cnt != 1)
+        Test::Fail(tostr() << "Expected one assign call, saw "
+                           << rebalance_cb.assign_call_cnt << "\n");
+      Test::delete_topic(c, topic_name_1.c_str());
+      deleted = true;
+    }
+
+    if (Test::assignment_partition_count(c, NULL) == 0 && deleted) {
+      Test::Say(tostr() << "Assignment is empty following deletion of topic\n");
+      done = true;
+    }
+  }
+
+  Test::Say("Closing consumer\n");
+  c->close();
+
+  delete c;
+
+  SUB_TEST_PASS();
+}
+
+
+
+/* Check behavior when:
+ *   1. single consumer (without rebalance_cb) subscribes to a single topic.
+ *   2. that topic is deleted leaving no topics.
+ *   3. consumer is closed.
+ */
+
+static void j_delete_topic_no_rb_callback() {
+  SUB_TEST();
+
+  std::string topic_name_1 =
+      Test::mk_topic_name("0113-cooperative_rebalance", 1);
+  test_create_topic(NULL, topic_name_1.c_str(), 1, 1);
+
+  std::string group_name =
+      Test::mk_unique_group_name("0113-cooperative_rebalance");
+
+  std::vector<std::pair<std::string, std::string> > additional_conf;
+  additional_conf.push_back(std::pair<std::string, std::string>(
+      std::string("topic.metadata.refresh.interval.ms"), std::string("3000")));
+  RdKafka::KafkaConsumer *c = make_consumer(
+      "C_1", group_name, "cooperative-sticky", &additional_conf, NULL, 15);
+  test_wait_topic_exists(c->c_ptr(), topic_name_1.c_str(), 10 * 1000);
+
+  Test::subscribe(c, topic_name_1);
+
+  bool deleted = false;
+  bool done    = false;
+  while (!done) {
+    Test::poll_once(c, 500);
+
+    if (Test::assignment_partition_count(c, NULL) == 1 && !deleted) {
+      Test::delete_topic(c, topic_name_1.c_str());
+      deleted = true;
+    }
+
+    if (Test::assignment_partition_count(c, NULL) == 0 && deleted) {
+      Test::Say(tostr() << "Assignment is empty following deletion of topic\n");
+      done = true;
+    }
+  }
+
+  Test::Say("Closing consumer\n");
+  c->close();
+
+  delete c;
+
+  SUB_TEST_PASS();
+}
+
+
+
+/* Check behavior when:
+ *   1. Single consumer (rebalance_cb) subscribes to a 1 partition topic.
+ *   2. Number of partitions is increased to 2.
+ *   3. Consumer is closed.
+ */
+
+static void k_add_partition() {
+  SUB_TEST();
+
+  std::string topic_name = Test::mk_topic_name("0113-cooperative_rebalance", 1);
+  test_create_topic(NULL, topic_name.c_str(), 1, 1);
+
+  std::string group_name =
+      Test::mk_unique_group_name("0113-cooperative_rebalance");
+
+  std::vector<std::pair<std::string, std::string> > additional_conf;
+  additional_conf.push_back(std::pair<std::string, std::string>(
+      std::string("topic.metadata.refresh.interval.ms"), std::string("3000")));
+  DefaultRebalanceCb rebalance_cb;
+  RdKafka::KafkaConsumer *c =
+      make_consumer("C_1", group_name, "cooperative-sticky", &additional_conf,
+                    &rebalance_cb, 15);
+  test_wait_topic_exists(c->c_ptr(), topic_name.c_str(), 10 * 1000);
+
+  Test::subscribe(c, topic_name);
+
+  bool subscribed = false;
+  bool done       = false;
+  while (!done) {
+    Test::poll_once(c, 500);
+
+    if (Test::assignment_partition_count(c, NULL) == 1 && !subscribed) {
+      if (rebalance_cb.assign_call_cnt != 1)
+        Test::Fail(tostr() << "Expected 1 assign call, saw "
+                           << rebalance_cb.assign_call_cnt);
+      if (rebalance_cb.revoke_call_cnt != 0)
+        Test::Fail(tostr() << "Expected 0 revoke calls, saw "
+                           << rebalance_cb.revoke_call_cnt);
+      Test::create_partitions(c, topic_name.c_str(), 2);
+      subscribed = true;
+    }
+
+    if (Test::assignment_partition_count(c, NULL) == 2 && subscribed) {
+      if (rebalance_cb.assign_call_cnt != 2)
+        Test::Fail(tostr() << "Expected 2 assign calls, saw "
+                           << rebalance_cb.assign_call_cnt);
+      if (rebalance_cb.revoke_call_cnt != 0)
+        Test::Fail(tostr() << "Expected 0 revoke calls, saw "
+                           << rebalance_cb.revoke_call_cnt);
+      done = true;
+    }
+  }
+
+  Test::Say("Closing consumer\n");
+  c->close();
+  delete c;
+
+  if (rebalance_cb.assign_call_cnt != 2)
+    Test::Fail(tostr() << "Expected 2 assign calls, saw "
+                       << rebalance_cb.assign_call_cnt);
+  if (rebalance_cb.revoke_call_cnt != 1)
+    Test::Fail(tostr() << "Expected 1 revoke call, saw "
+                       << rebalance_cb.revoke_call_cnt);
+
+  SUB_TEST_PASS();
+}
+
+
+
+/* Check behavior when:
+ *   1. two consumers (with rebalance_cb's) subscribe to two topics.
+ *   2. one of the consumers calls unsubscribe.
+ *   3. consumers closed.
+ */
+
+static void l_unsubscribe() {
+  SUB_TEST();
+
+  std::string topic_name_1 =
+      Test::mk_topic_name("0113-cooperative_rebalance", 1);
+  std::string topic_name_2 =
+      Test::mk_topic_name("0113-cooperative_rebalance", 1);
+  std::string group_name =
+      Test::mk_unique_group_name("0113-cooperative_rebalance");
+  test_create_topic(NULL, topic_name_1.c_str(), 2, 1);
+  test_create_topic(NULL, topic_name_2.c_str(), 2, 1);
+
+  DefaultRebalanceCb rebalance_cb1;
+  RdKafka::KafkaConsumer *c1 = make_consumer(
+      "C_1", group_name, "cooperative-sticky", NULL, &rebalance_cb1, 30);
+  test_wait_topic_exists(c1->c_ptr(), topic_name_1.c_str(), 10 * 1000);
+  test_wait_topic_exists(c1->c_ptr(), topic_name_2.c_str(), 10 * 1000);
+
+  Test::subscribe(c1, topic_name_1, topic_name_2);
+
+  DefaultRebalanceCb rebalance_cb2;
+  RdKafka::KafkaConsumer *c2 = make_consumer(
+      "C_2", group_name, "cooperative-sticky", NULL, &rebalance_cb2, 30);
+  Test::subscribe(c2, topic_name_1, topic_name_2);
+
+  bool done         = false;
+  bool unsubscribed = false;
+  while (!done) {
+    Test::poll_once(c1, 500);
+    Test::poll_once(c2, 500);
+
+    if (Test::assignment_partition_count(c1, NULL) == 2 &&
+        Test::assignment_partition_count(c2, NULL) == 2) {
+      if (rebalance_cb1.assign_call_cnt != 1)
+        Test::Fail(
+            tostr() << "Expecting consumer 1's assign_call_cnt to be 1 not: "
+                    << rebalance_cb1.assign_call_cnt);
+      if (rebalance_cb2.assign_call_cnt != 1)
+        Test::Fail(
+            tostr() << "Expecting consumer 2's assign_call_cnt to be 1 not: "
+                    << rebalance_cb2.assign_call_cnt);
+      Test::Say("Unsubscribing consumer 1 from both topics\n");
+      c1->unsubscribe();
+      unsubscribed = true;
+    }
+
+    if (unsubscribed && Test::assignment_partition_count(c1, NULL) == 0 &&
+        Test::assignment_partition_count(c2, NULL) == 4) {
+      if (rebalance_cb1.assign_call_cnt !=
+          1) /* is now unsubscribed, so rebalance_cb will no longer be called.
+              */
+        Test::Fail(
+            tostr() << "Expecting consumer 1's assign_call_cnt to be 1 not: "
+                    << rebalance_cb1.assign_call_cnt);
+      if (rebalance_cb2.assign_call_cnt != 2)
+        Test::Fail(
+            tostr() << "Expecting consumer 2's assign_call_cnt to be 2 not: "
+                    << rebalance_cb2.assign_call_cnt);
+      if (rebalance_cb1.revoke_call_cnt != 1)
+        Test::Fail(
+            tostr() << "Expecting consumer 1's revoke_call_cnt to be 1 not: "
+                    << rebalance_cb1.revoke_call_cnt);
+      if (rebalance_cb2.revoke_call_cnt !=
+          0) /* the rebalance_cb should not be called if the revoked partition
+                list is empty */
+        Test::Fail(
+            tostr() << "Expecting consumer 2's revoke_call_cnt to be 0 not: "
+                    << rebalance_cb2.revoke_call_cnt);
+      Test::Say("Unsubscribe completed");
+      done = true;
+    }
+  }
+
+  Test::Say("Closing consumer 1\n");
+  c1->close();
+  Test::Say("Closing consumer 2\n");
+  c2->close();
+
+  /* there should be no assign rebalance_cb calls on close */
+  if (rebalance_cb1.assign_call_cnt != 1)
+    Test::Fail(tostr() << "Expecting consumer 1's assign_call_cnt to be 1 not: "
+                       << rebalance_cb1.assign_call_cnt);
+  if (rebalance_cb2.assign_call_cnt != 2)
+    Test::Fail(tostr() << "Expecting consumer 2's assign_call_cnt to be 2 not: "
+                       << rebalance_cb2.assign_call_cnt);
+
+  if (rebalance_cb1.revoke_call_cnt !=
+      1) /* should not be called a second revoke rebalance_cb */
+    Test::Fail(tostr() << "Expecting consumer 1's revoke_call_cnt to be 1 not: "
+                       << rebalance_cb1.revoke_call_cnt);
+  if (rebalance_cb2.revoke_call_cnt != 1)
+    Test::Fail(tostr() << "Expecting consumer 2's revoke_call_cnt to be 1 not: "
+                       << rebalance_cb2.revoke_call_cnt);
+
+  if (rebalance_cb1.lost_call_cnt != 0)
+    Test::Fail(tostr() << "Expecting consumer 1's lost_call_cnt to be 0, not: "
+                       << rebalance_cb1.lost_call_cnt);
+  if (rebalance_cb2.lost_call_cnt != 0)
+    Test::Fail(tostr() << "Expecting consumer 2's lost_call_cnt to be 0, not: "
+                       << rebalance_cb2.lost_call_cnt);
+
+  delete c1;
+  delete c2;
+
+  SUB_TEST_PASS();
+}
+
+
+
+/* Check behavior when:
+ *   1. A consumers (with no rebalance_cb) subscribes to a topic.
+ *   2. The consumer calls unsubscribe.
+ *   3. Consumers closed.
+ */
+
+static void m_unsubscribe_2() {
+  SUB_TEST();
+
+  std::string topic_name = Test::mk_topic_name("0113-cooperative_rebalance", 1);
+  std::string group_name =
+      Test::mk_unique_group_name("0113-cooperative_rebalance");
+  test_create_topic(NULL, topic_name.c_str(), 2, 1);
+
+  RdKafka::KafkaConsumer *c =
+      make_consumer("C_1", group_name, "cooperative-sticky", NULL, NULL, 15);
+  test_wait_topic_exists(c->c_ptr(), topic_name.c_str(), 10 * 1000);
+
+  Test::subscribe(c, topic_name);
+
+  bool done         = false;
+  bool unsubscribed = false;
+  while (!done) {
+    Test::poll_once(c, 500);
+
+    if (Test::assignment_partition_count(c, NULL) == 2) {
+      Test::unsubscribe(c);
+      unsubscribed = true;
+    }
+
+    if (unsubscribed && Test::assignment_partition_count(c, NULL) == 0) {
+      Test::Say("Unsubscribe completed");
+      done = true;
+    }
+  }
+
+  Test::Say("Closing consumer\n");
+  c->close();
+
+  delete c;
+
+  SUB_TEST_PASS();
+}
+
+
+
+/* Check behavior when:
+ *   1. Two consumers (with rebalance_cb) subscribe to a regex (no matching
+ * topics exist)
+ *   2. Create two topics.
+ *   3. Remove one of the topics.
+ *   3. Consumers closed.
+ */
+
+static void n_wildcard() {
+  SUB_TEST();
+
+  const string topic_base_name = Test::mk_topic_name("0113-n_wildcard", 1);
+  const string topic_name_1    = topic_base_name + "_1";
+  const string topic_name_2    = topic_base_name + "_2";
+  const string topic_regex     = "^" + topic_base_name + "_.";
+  const string group_name      = Test::mk_unique_group_name("0113-n_wildcard");
+
+  std::vector<std::pair<std::string, std::string> > additional_conf;
+  additional_conf.push_back(std::pair<std::string, std::string>(
+      std::string("topic.metadata.refresh.interval.ms"), std::string("3000")));
+
+  DefaultRebalanceCb rebalance_cb1;
+  RdKafka::KafkaConsumer *c1 =
+      make_consumer("C_1", group_name, "cooperative-sticky", &additional_conf,
+                    &rebalance_cb1, 30);
+  Test::subscribe(c1, topic_regex);
+
+  DefaultRebalanceCb rebalance_cb2;
+  RdKafka::KafkaConsumer *c2 =
+      make_consumer("C_2", group_name, "cooperative-sticky", &additional_conf,
+                    &rebalance_cb2, 30);
+  Test::subscribe(c2, topic_regex);
+
+  /* There are no matching topics, so the consumers should not join the group
+   * initially */
+  Test::poll_once(c1, 500);
+  Test::poll_once(c2, 500);
+
+  if (rebalance_cb1.assign_call_cnt != 0)
+    Test::Fail(tostr() << "Expecting consumer 1's assign_call_cnt to be 0 not: "
+                       << rebalance_cb1.assign_call_cnt);
+  if (rebalance_cb2.assign_call_cnt != 0)
+    Test::Fail(tostr() << "Expecting consumer 2's assign_call_cnt to be 0 not: "
+                       << rebalance_cb2.assign_call_cnt);
+
+  bool done                    = false;
+  bool created_topics          = false;
+  bool deleted_topic           = false;
+  int last_cb1_assign_call_cnt = 0;
+  int last_cb2_assign_call_cnt = 0;
+  while (!done) {
+    Test::poll_once(c1, 500);
+    Test::poll_once(c2, 500);
+
+    if (Test::assignment_partition_count(c1, NULL) == 0 &&
+        Test::assignment_partition_count(c2, NULL) == 0 && !created_topics) {
+      Test::Say(
+          "Creating two topics with 2 partitions each that match regex\n");
+      test_create_topic(NULL, topic_name_1.c_str(), 2, 1);
+      test_create_topic(NULL, topic_name_2.c_str(), 2, 1);
+      /* The consumers should autonomously discover these topics and start
+       * consuming from them. This happens in the background - is not
+       * influenced by whether we wait for the topics to be created before
+       * continuing the main loop. It is possible that both topics are
+       * discovered simultaneously, requiring a single rebalance OR that
+       * topic 1 is discovered first (it was created first), a rebalance
+       * initiated, then topic 2 discovered, then another rebalance
+       * initiated to include it.
+       */
+      created_topics = true;
+    }
+
+    if (Test::assignment_partition_count(c1, NULL) == 2 &&
+        Test::assignment_partition_count(c2, NULL) == 2 && !deleted_topic) {
+      if (rebalance_cb1.nonempty_assign_call_cnt == 1) {
+        /* just one rebalance was required */
+        TEST_ASSERT(rebalance_cb1.nonempty_assign_call_cnt == 1,
+                    "Expecting C_1's nonempty_assign_call_cnt to be 1 not %d ",
+                    rebalance_cb1.nonempty_assign_call_cnt);
+        TEST_ASSERT(rebalance_cb2.nonempty_assign_call_cnt == 1,
+                    "Expecting C_2's nonempty_assign_call_cnt to be 1 not %d ",
+                    rebalance_cb2.nonempty_assign_call_cnt);
+      } else {
+        /* two rebalances were required (occurs infrequently) */
+        TEST_ASSERT(rebalance_cb1.nonempty_assign_call_cnt == 2,
+                    "Expecting C_1's nonempty_assign_call_cnt to be 2 not %d ",
+                    rebalance_cb1.nonempty_assign_call_cnt);
+        TEST_ASSERT(rebalance_cb2.nonempty_assign_call_cnt == 2,
+                    "Expecting C_2's nonempty_assign_call_cnt to be 2 not %d ",
+                    rebalance_cb2.nonempty_assign_call_cnt);
+      }
+
+      TEST_ASSERT(rebalance_cb1.revoke_call_cnt == 0,
+                  "Expecting C_1's revoke_call_cnt to be 0 not %d ",
+                  rebalance_cb1.revoke_call_cnt);
+      TEST_ASSERT(rebalance_cb2.revoke_call_cnt == 0,
+                  "Expecting C_2's revoke_call_cnt to be 0 not %d ",
+                  rebalance_cb2.revoke_call_cnt);
+
+      last_cb1_assign_call_cnt = rebalance_cb1.assign_call_cnt;
+      last_cb2_assign_call_cnt = rebalance_cb2.assign_call_cnt;
+
+      Test::Say("Deleting topic 1\n");
+      Test::delete_topic(c1, topic_name_1.c_str());
+      deleted_topic = true;
+    }
+
+    if (Test::assignment_partition_count(c1, NULL) == 1 &&
+        Test::assignment_partition_count(c2, NULL) == 1 && deleted_topic) {
+      /* accumulated in lost case as well */
+      TEST_ASSERT(rebalance_cb1.revoke_call_cnt == 1,
+                  "Expecting C_1's revoke_call_cnt to be 1 not %d",
+                  rebalance_cb1.revoke_call_cnt);
+      TEST_ASSERT(rebalance_cb2.revoke_call_cnt == 1,
+                  "Expecting C_2's revoke_call_cnt to be 1 not %d",
+                  rebalance_cb2.revoke_call_cnt);
+      TEST_ASSERT(rebalance_cb1.lost_call_cnt == 1,
+                  "Expecting C_1's lost_call_cnt to be 1 not %d",
+                  rebalance_cb1.lost_call_cnt);
+      TEST_ASSERT(rebalance_cb2.lost_call_cnt == 1,
+                  "Expecting C_2's lost_call_cnt to be 1 not %d",
+                  rebalance_cb2.lost_call_cnt);
+
+      /* Consumers will rejoin group after revoking the lost partitions.
+       * this will result in an rebalance_cb assign (empty partitions).
+       * it follows the revoke, which has already been confirmed to have
+       * happened. */
+      Test::Say("Waiting for rebalance_cb assigns\n");
+      while (rebalance_cb1.assign_call_cnt == last_cb1_assign_call_cnt ||
+             rebalance_cb2.assign_call_cnt == last_cb2_assign_call_cnt) {
+        Test::poll_once(c1, 500);
+        Test::poll_once(c2, 500);
+      }
+
+      Test::Say("Consumers are subscribed to one partition each\n");
+      done = true;
+    }
+  }
+
+  Test::Say("Closing consumer 1\n");
+  last_cb1_assign_call_cnt = rebalance_cb1.assign_call_cnt;
+  c1->close();
+
+  /* There should be no assign rebalance_cb calls on close */
+  TEST_ASSERT(rebalance_cb1.assign_call_cnt == last_cb1_assign_call_cnt,
+              "Expecting C_1's assign_call_cnt to be %d not %d",
+              last_cb1_assign_call_cnt, rebalance_cb1.assign_call_cnt);
+
+  /* Let C_2 catch up on the rebalance and get assigned C_1's partitions. */
+  last_cb2_assign_call_cnt = rebalance_cb2.nonempty_assign_call_cnt;
+  while (rebalance_cb2.nonempty_assign_call_cnt == last_cb2_assign_call_cnt)
+    Test::poll_once(c2, 500);
+
+  Test::Say("Closing consumer 2\n");
+  last_cb2_assign_call_cnt = rebalance_cb2.assign_call_cnt;
+  c2->close();
+
+  /* There should be no assign rebalance_cb calls on close */
+  TEST_ASSERT(rebalance_cb2.assign_call_cnt == last_cb2_assign_call_cnt,
+              "Expecting C_2's assign_call_cnt to be %d not %d",
+              last_cb2_assign_call_cnt, rebalance_cb2.assign_call_cnt);
+
+  TEST_ASSERT(rebalance_cb1.revoke_call_cnt == 2,
+              "Expecting C_1's revoke_call_cnt to be 2 not %d",
+              rebalance_cb1.revoke_call_cnt);
+  TEST_ASSERT(rebalance_cb2.revoke_call_cnt == 2,
+              "Expecting C_2's revoke_call_cnt to be 2 not %d",
+              rebalance_cb2.revoke_call_cnt);
+
+  TEST_ASSERT(rebalance_cb1.lost_call_cnt == 1,
+              "Expecting C_1's lost_call_cnt to be 1, not %d",
+              rebalance_cb1.lost_call_cnt);
+  TEST_ASSERT(rebalance_cb2.lost_call_cnt == 1,
+              "Expecting C_2's lost_call_cnt to be 1, not %d",
+              rebalance_cb2.lost_call_cnt);
+
+  delete c1;
+  delete c2;
+
+  SUB_TEST_PASS();
+}
+
+
+
+/* Check behavior when:
+ *   1. Consumer (librdkafka) subscribes to two topics (2 and 6 partitions).
+ *   2. Consumer (java) subscribes to the same two topics.
+ *   3. Consumer (librdkafka) unsubscribes from the two partition topic.
+ *   4. Consumer (java) process closes upon detecting the above unsubscribe.
+ *   5. Consumer (librdkafka) will now be subscribed to 6 partitions.
+ *   6. Close librdkafka consumer.
+ */
+
+static void o_java_interop() {
+  SUB_TEST();
+
+  if (*test_conf_get(NULL, "sasl.mechanism") != '\0')
+    SUB_TEST_SKIP(
+        "Cluster is set up for SASL: we won't bother with that "
+        "for the Java client\n");
+
+  std::string topic_name_1 = Test::mk_topic_name("0113_o_2", 1);
+  std::string topic_name_2 = Test::mk_topic_name("0113_o_6", 1);
+  std::string group_name   = Test::mk_unique_group_name("0113_o");
+  test_create_topic(NULL, topic_name_1.c_str(), 2, 1);
+  test_create_topic(NULL, topic_name_2.c_str(), 6, 1);
+
+  DefaultRebalanceCb rebalance_cb;
+  RdKafka::KafkaConsumer *c = make_consumer(
+      "C_1", group_name, "cooperative-sticky", NULL, &rebalance_cb, 25);
+  test_wait_topic_exists(c->c_ptr(), topic_name_1.c_str(), 10 * 1000);
+  test_wait_topic_exists(c->c_ptr(), topic_name_2.c_str(), 10 * 1000);
+
+  Test::subscribe(c, topic_name_1, topic_name_2);
+
+  bool done                      = false;
+  bool changed_subscription      = false;
+  bool changed_subscription_done = false;
+  int java_pid                   = 0;
+  while (!done) {
+    Test::poll_once(c, 500);
+
+    if (1)  // FIXME: Remove after debugging
+      Test::Say(tostr() << "Assignment partition count: "
+                        << Test::assignment_partition_count(c, NULL)
+                        << ", changed_sub " << changed_subscription
+                        << ", changed_sub_done " << changed_subscription_done
+                        << ", assign_call_cnt " << rebalance_cb.assign_call_cnt
+                        << "\n");
+    if (Test::assignment_partition_count(c, NULL) == 8 && !java_pid) {
+      Test::Say(_C_GRN "librdkafka consumer assigned to 8 partitions\n");
+      string bootstrapServers = get_bootstrap_servers();
+      const char *argv[1 + 1 + 1 + 1 + 1 + 1];
+      size_t i  = 0;
+      argv[i++] = "test1";
+      argv[i++] = bootstrapServers.c_str();
+      argv[i++] = topic_name_1.c_str();
+      argv[i++] = topic_name_2.c_str();
+      argv[i++] = group_name.c_str();
+      argv[i]   = NULL;
+      java_pid  = test_run_java("IncrementalRebalanceCli", argv);
+      if (java_pid <= 0)
+        Test::Fail(tostr() << "Unexpected pid: " << java_pid);
+    }
+
+    if (Test::assignment_partition_count(c, NULL) == 4 && java_pid != 0 &&
+        !changed_subscription) {
+      if (rebalance_cb.assign_call_cnt != 2)
+        Test::Fail(tostr() << "Expecting consumer's assign_call_cnt to be 2, "
+                              "not "
+                           << rebalance_cb.assign_call_cnt);
+      Test::Say(_C_GRN "Java consumer is now part of the group\n");
+      Test::subscribe(c, topic_name_1);
+      changed_subscription = true;
+    }
+
+    /* Depending on the timing of resubscribe rebalancing and the
+     * Java consumer terminating we might have one or two rebalances,
+     * hence the fuzzy <=5 and >=5 checks. */
+    if (Test::assignment_partition_count(c, NULL) == 2 &&
+        changed_subscription && rebalance_cb.assign_call_cnt <= 5 &&
+        !changed_subscription_done) {
+      /* All topic 1 partitions will be allocated to this consumer whether or
+       * not the Java consumer has unsubscribed yet because the sticky algorithm
+       * attempts to ensure partition counts are even. */
+      Test::Say(_C_GRN "Consumer 1 has unsubscribed from topic 2\n");
+      changed_subscription_done = true;
+    }
+
+    if (Test::assignment_partition_count(c, NULL) == 2 &&
+        changed_subscription && rebalance_cb.assign_call_cnt >= 5 &&
+        changed_subscription_done) {
+      /* When the java consumer closes, this will cause an empty assign
+       * rebalance_cb event, allowing detection of when this has happened. */
+      Test::Say(_C_GRN "Java consumer has left the group\n");
+      done = true;
+    }
+  }
+
+  Test::Say("Closing consumer\n");
+  c->close();
+
+  /* Expected behavior is IncrementalRebalanceCli will exit cleanly, timeout
+   * otherwise. */
+  test_waitpid(java_pid);
+
+  delete c;
+
+  SUB_TEST_PASS();
+}
+
+
+
+/* Check behavior when:
+ *  - Single consumer subscribes to topic.
+ *  - Soon after (timing such that rebalance is probably in progress) it
+ * subscribes to a different topic.
+ */
+
+static void s_subscribe_when_rebalancing(int variation) {
+  SUB_TEST("variation %d", variation);
+
+  std::string topic_name_1 =
+      Test::mk_topic_name("0113-cooperative_rebalance", 1);
+  std::string topic_name_2 =
+      Test::mk_topic_name("0113-cooperative_rebalance", 1);
+  std::string topic_name_3 =
+      Test::mk_topic_name("0113-cooperative_rebalance", 1);
+  std::string group_name =
+      Test::mk_unique_group_name("0113-cooperative_rebalance");
+  test_create_topic(NULL, topic_name_1.c_str(), 1, 1);
+  test_create_topic(NULL, topic_name_2.c_str(), 1, 1);
+  test_create_topic(NULL, topic_name_3.c_str(), 1, 1);
+
+  DefaultRebalanceCb rebalance_cb;
+  RdKafka::KafkaConsumer *c = make_consumer(
+      "C_1", group_name, "cooperative-sticky", NULL, &rebalance_cb, 25);
+  test_wait_topic_exists(c->c_ptr(), topic_name_1.c_str(), 10 * 1000);
+  test_wait_topic_exists(c->c_ptr(), topic_name_2.c_str(), 10 * 1000);
+  test_wait_topic_exists(c->c_ptr(), topic_name_3.c_str(), 10 * 1000);
+
+  if (variation == 2 || variation == 4 || variation == 6) {
+    /* Pre-cache metadata for all topics. */
+    class RdKafka::Metadata *metadata;
+    c->metadata(true, NULL, &metadata, 5000);
+    delete metadata;
+  }
+
+  Test::subscribe(c, topic_name_1);
+  Test::wait_for_assignment(c, 1, &topic_name_1);
+
+  Test::subscribe(c, topic_name_2);
+
+  if (variation == 3 || variation == 5)
+    Test::poll_once(c, 500);
+
+  if (variation < 5) {
+    // Very quickly after subscribing to topic 2, subscribe to topic 3.
+    Test::subscribe(c, topic_name_3);
+    Test::wait_for_assignment(c, 1, &topic_name_3);
+  } else {
+    // ..or unsubscribe.
+    Test::unsubscribe(c);
+    Test::wait_for_assignment(c, 0, NULL);
+  }
+
+  delete c;
+
+  SUB_TEST_PASS();
+}
+
+
+
+/* Check behavior when:
+ *  - Two consumer subscribe to a topic.
+ *  - Max poll interval is exceeded on the first consumer.
+ */
+
+static void t_max_poll_interval_exceeded(int variation) {
+  SUB_TEST("variation %d", variation);
+
+  std::string topic_name_1 =
+      Test::mk_topic_name("0113-cooperative_rebalance", 1);
+  std::string group_name =
+      Test::mk_unique_group_name("0113-cooperative_rebalance");
+  test_create_topic(NULL, topic_name_1.c_str(), 2, 1);
+
+  std::vector<std::pair<std::string, std::string> > additional_conf;
+  additional_conf.push_back(std::pair<std::string, std::string>(
+      std::string("session.timeout.ms"), std::string("6000")));
+  additional_conf.push_back(std::pair<std::string, std::string>(
+      std::string("max.poll.interval.ms"), std::string("7000")));
+
+  DefaultRebalanceCb rebalance_cb1;
+  RdKafka::KafkaConsumer *c1 =
+      make_consumer("C_1", group_name, "cooperative-sticky", &additional_conf,
+                    &rebalance_cb1, 30);
+  DefaultRebalanceCb rebalance_cb2;
+  RdKafka::KafkaConsumer *c2 =
+      make_consumer("C_2", group_name, "cooperative-sticky", &additional_conf,
+                    &rebalance_cb2, 30);
+
+  test_wait_topic_exists(c1->c_ptr(), topic_name_1.c_str(), 10 * 1000);
+  test_wait_topic_exists(c2->c_ptr(), topic_name_1.c_str(), 10 * 1000);
+
+  Test::subscribe(c1, topic_name_1);
+  Test::subscribe(c2, topic_name_1);
+
+  bool done                    = false;
+  bool both_have_been_assigned = false;
+  while (!done) {
+    if (!both_have_been_assigned)
+      Test::poll_once(c1, 500);
+    Test::poll_once(c2, 500);
+
+    if (Test::assignment_partition_count(c1, NULL) == 1 &&
+        Test::assignment_partition_count(c2, NULL) == 1 &&
+        !both_have_been_assigned) {
+      Test::Say(
+          tostr()
+          << "Both consumers are assigned to topic " << topic_name_1
+          << ". WAITING 7 seconds for max.poll.interval.ms to be exceeded\n");
+      both_have_been_assigned = true;
+    }
+
+    if (Test::assignment_partition_count(c2, NULL) == 2 &&
+        both_have_been_assigned) {
+      Test::Say("Consumer 1 is no longer assigned any partitions, done\n");
+      done = true;
+    }
+  }
+
+  if (variation == 1) {
+    if (rebalance_cb1.lost_call_cnt != 0)
+      Test::Fail(
+          tostr() << "Expected consumer 1 lost revoke count to be 0, not: "
+                  << rebalance_cb1.lost_call_cnt);
+    Test::poll_once(c1,
+                    500); /* Eat the max poll interval exceeded error message */
+    Test::poll_once(c1,
+                    500); /* Trigger the rebalance_cb with lost partitions */
+    if (rebalance_cb1.lost_call_cnt != 1)
+      Test::Fail(
+          tostr() << "Expected consumer 1 lost revoke count to be 1, not: "
+                  << rebalance_cb1.lost_call_cnt);
+  }
+
+  c1->close();
+  c2->close();
+
+  if (rebalance_cb1.lost_call_cnt != 1)
+    Test::Fail(tostr() << "Expected consumer 1 lost revoke count to be 1, not: "
+                       << rebalance_cb1.lost_call_cnt);
+
+  if (rebalance_cb1.assign_call_cnt != 1)
+    Test::Fail(tostr() << "Expected consumer 1 assign count to be 1, not: "
+                       << rebalance_cb1.assign_call_cnt);
+  if (rebalance_cb2.assign_call_cnt != 2)
+    Test::Fail(tostr() << "Expected consumer 1 assign count to be 2, not: "
+                       << rebalance_cb1.assign_call_cnt);
+
+  if (rebalance_cb1.revoke_call_cnt != 1)
+    Test::Fail(tostr() << "Expected consumer 1 revoke count to be 1, not: "
+                       << rebalance_cb1.revoke_call_cnt);
+  if (rebalance_cb2.revoke_call_cnt != 1)
+    Test::Fail(tostr() << "Expected consumer 2 revoke count to be 1, not: "
+                       << rebalance_cb1.revoke_call_cnt);
+
+  delete c1;
+  delete c2;
+
+  SUB_TEST_PASS();
+}
+
+
+/**
+ * @brief Poll all consumers until there are no more events or messages
+ *        and the timeout has expired.
+ */
+static void poll_all_consumers(RdKafka::KafkaConsumer **consumers,
+                               DefaultRebalanceCb *rebalance_cbs,
+                               size_t num,
+                               int timeout_ms) {
+  int64_t ts_end = test_clock() + (timeout_ms * 1000);
+
+  /* Poll all consumers until no more events are seen,
+   * this makes sure we exhaust the current state events before returning. */
+  bool evented;
+  do {
+    evented = false;
+    for (size_t i = 0; i < num; i++) {
+      int block_ms = min(10, (int)((ts_end - test_clock()) / 1000));
+      while (rebalance_cbs[i].poll_once(consumers[i], max(block_ms, 0)))
+        evented = true;
+    }
+  } while (evented || test_clock() < ts_end);
+}
+
+
+/**
+ * @brief Stress test with 8 consumers subscribing, fetching and committing.
+ *
+ * @param subscription_variation 0..2
+ *
+ * TODO: incorporate committing offsets.
+ */
+
+static void u_multiple_subscription_changes(bool use_rebalance_cb,
+                                            int subscription_variation) {
+  const int N_CONSUMERS          = 8;
+  const int N_TOPICS             = 2;
+  const int N_PARTS_PER_TOPIC    = N_CONSUMERS * N_TOPICS;
+  const int N_PARTITIONS         = N_PARTS_PER_TOPIC * N_TOPICS;
+  const int N_MSGS_PER_PARTITION = 1000;
+
+  SUB_TEST("use_rebalance_cb: %d, subscription_variation: %d",
+           (int)use_rebalance_cb, subscription_variation);
+
+  string topic_name_1 = Test::mk_topic_name("0113u_1", 1);
+  string topic_name_2 = Test::mk_topic_name("0113u_2", 1);
+  string group_name   = Test::mk_unique_group_name("0113u");
+
+  test_create_topic(NULL, topic_name_1.c_str(), N_PARTS_PER_TOPIC, 1);
+  test_create_topic(NULL, topic_name_2.c_str(), N_PARTS_PER_TOPIC, 1);
+
+  Test::Say("Creating consumers\n");
+  DefaultRebalanceCb rebalance_cbs[N_CONSUMERS];
+  RdKafka::KafkaConsumer *consumers[N_CONSUMERS];
+
+  for (int i = 0; i < N_CONSUMERS; i++) {
+    std::string name = tostr() << "C_" << i;
+    consumers[i] =
+        make_consumer(name.c_str(), group_name, "cooperative-sticky", NULL,
+                      use_rebalance_cb ? &rebalance_cbs[i] : NULL, 120);
+  }
+
+  test_wait_topic_exists(consumers[0]->c_ptr(), topic_name_1.c_str(),
+                         10 * 1000);
+  test_wait_topic_exists(consumers[0]->c_ptr(), topic_name_2.c_str(),
+                         10 * 1000);
+
+
+  /*
+   * Seed all partitions with the same number of messages so we later can
+   * verify that consumption is working.
+   */
+  vector<pair<Toppar, int> > ptopics;
+  ptopics.push_back(pair<Toppar, int>(Toppar(topic_name_1, N_PARTS_PER_TOPIC),
+                                      N_MSGS_PER_PARTITION));
+  ptopics.push_back(pair<Toppar, int>(Toppar(topic_name_2, N_PARTS_PER_TOPIC),
+                                      N_MSGS_PER_PARTITION));
+  produce_msgs(ptopics);
+
+
+  /*
+   * Track what topics a consumer should be subscribed to and use this to
+   * verify both its subscription and assignment throughout the test.
+   */
+
+  /* consumer -> currently subscribed topics */
+  map<int, vector<string> > consumer_topics;
+
+  /* topic -> consumers subscribed to topic */
+  map<string, set<int> > topic_consumers;
+
+  /* The subscription alternatives that consumers
+   * alter between in the playbook. */
+  vector<string> SUBSCRIPTION_1;
+  vector<string> SUBSCRIPTION_2;
+
+  SUBSCRIPTION_1.push_back(topic_name_1);
+
+  switch (subscription_variation) {
+  case 0:
+    SUBSCRIPTION_2.push_back(topic_name_1);
+    SUBSCRIPTION_2.push_back(topic_name_2);
+    break;
+
+  case 1:
+    SUBSCRIPTION_2.push_back(topic_name_2);
+    break;
+
+  case 2:
+    /* No subscription */
+    break;
+  }
+
+  sort(SUBSCRIPTION_1.begin(), SUBSCRIPTION_1.end());
+  sort(SUBSCRIPTION_2.begin(), SUBSCRIPTION_2.end());
+
+
+  /*
+   * Define playbook
+   */
+  const struct {
+    int timestamp_ms;
+    int consumer;
+    const vector<string> *topics;
+  } playbook[] = {/* timestamp_ms, consumer_number, subscribe-to-topics */
+                  {0, 0, &SUBSCRIPTION_1}, /* Cmd 0 */
+                  {4000, 1, &SUBSCRIPTION_1},  {4000, 1, &SUBSCRIPTION_1},
+                  {4000, 1, &SUBSCRIPTION_1},  {4000, 2, &SUBSCRIPTION_1},
+                  {6000, 3, &SUBSCRIPTION_1}, /* Cmd 5 */
+                  {6000, 4, &SUBSCRIPTION_1},  {6000, 5, &SUBSCRIPTION_1},
+                  {6000, 6, &SUBSCRIPTION_1},  {6000, 7, &SUBSCRIPTION_2},
+                  {6000, 1, &SUBSCRIPTION_1}, /* Cmd 10 */
+                  {6000, 1, &SUBSCRIPTION_2},  {6000, 1, &SUBSCRIPTION_1},
+                  {6000, 2, &SUBSCRIPTION_2},  {7000, 2, &SUBSCRIPTION_1},
+                  {7000, 1, &SUBSCRIPTION_2}, /* Cmd 15 */
+                  {8000, 0, &SUBSCRIPTION_2},  {8000, 1, &SUBSCRIPTION_1},
+                  {8000, 0, &SUBSCRIPTION_1},  {13000, 2, &SUBSCRIPTION_1},
+                  {13000, 1, &SUBSCRIPTION_2}, /* Cmd 20 */
+                  {13000, 5, &SUBSCRIPTION_2}, {14000, 6, &SUBSCRIPTION_2},
+                  {15000, 7, &SUBSCRIPTION_1}, {15000, 1, &SUBSCRIPTION_1},
+                  {15000, 5, &SUBSCRIPTION_1}, /* Cmd 25 */
+                  {15000, 6, &SUBSCRIPTION_1}, {INT_MAX, 0, 0}};
+
+  /*
+   * Run the playbook
+   */
+  int cmd_number    = 0;
+  uint64_t ts_start = test_clock();
+
+  while (playbook[cmd_number].timestamp_ms != INT_MAX) {
+    TEST_ASSERT(playbook[cmd_number].consumer < N_CONSUMERS);
+
+    Test::Say(tostr() << "Cmd #" << cmd_number << ": wait "
+                      << playbook[cmd_number].timestamp_ms << "ms\n");
+
+    poll_all_consumers(consumers, rebalance_cbs, N_CONSUMERS,
+                       playbook[cmd_number].timestamp_ms -
+                           (int)((test_clock() - ts_start) / 1000));
+
+    /* Verify consumer assignments match subscribed topics */
+    map<Toppar, RdKafka::KafkaConsumer *> all_assignments;
+    for (int i = 0; i < N_CONSUMERS; i++)
+      verify_consumer_assignment(
+          consumers[i], rebalance_cbs[i], consumer_topics[i],
+          /* Allow empty assignment */
+          true,
+          /* Allow mismatch between subscribed topics
+           * and actual assignment since we can't
+           * synchronize the last subscription
+           * to the current assignment due to
+           * an unknown number of rebalances required
+           * for the final assignment to settle.
+           * This is instead checked at the end of
+           * this test case. */
+          true, &all_assignments, -1 /* no msgcnt check*/);
+
+    int cid                          = playbook[cmd_number].consumer;
+    RdKafka::KafkaConsumer *consumer = consumers[playbook[cmd_number].consumer];
+    const vector<string> *topics     = playbook[cmd_number].topics;
+
+    /*
+     * Update our view of the consumer's subscribed topics and vice versa.
+     */
+    for (vector<string>::const_iterator it = consumer_topics[cid].begin();
+         it != consumer_topics[cid].end(); it++) {
+      topic_consumers[*it].erase(cid);
+    }
+
+    consumer_topics[cid].clear();
+
+    for (vector<string>::const_iterator it = topics->begin();
+         it != topics->end(); it++) {
+      consumer_topics[cid].push_back(*it);
+      topic_consumers[*it].insert(cid);
+    }
+
+    RdKafka::ErrorCode err;
+
+    /*
+     * Change subscription
+     */
+    if (!topics->empty()) {
+      Test::Say(tostr() << "Consumer: " << consumer->name()
+                        << " is subscribing to topics "
+                        << string_vec_to_str(*topics) << " after "
+                        << ((test_clock() - ts_start) / 1000) << "ms\n");
+      err = consumer->subscribe(*topics);
+      TEST_ASSERT(!err, "Expected subscribe() to succeed, got %s",
+                  RdKafka::err2str(err).c_str());
+    } else {
+      Test::Say(tostr() << "Consumer: " << consumer->name()
+                        << " is unsubscribing after "
+                        << ((test_clock() - ts_start) / 1000) << "ms\n");
+      Test::unsubscribe(consumer);
+    }
+
+    /* Mark this consumer as waiting for rebalance so that
+     * verify_consumer_assignment() allows assigned partitions that
+     * (no longer) match the subscription. */
+    rebalance_cbs[cid].wait_rebalance = true;
+
+
+    /*
+     * Verify subscription matches what we think it should be.
+     */
+    vector<string> subscription;
+    err = consumer->subscription(subscription);
+    TEST_ASSERT(!err, "consumer %s subscription() failed: %s",
+                consumer->name().c_str(), RdKafka::err2str(err).c_str());
+
+    sort(subscription.begin(), subscription.end());
+
+    Test::Say(tostr() << "Consumer " << consumer->name()
+                      << " subscription is now "
+                      << string_vec_to_str(subscription) << "\n");
+
+    if (subscription != *topics)
+      Test::Fail(tostr() << "Expected consumer " << consumer->name()
+                         << " subscription: " << string_vec_to_str(*topics)
+                         << " but got: " << string_vec_to_str(subscription));
+
+    cmd_number++;
+  }
+
+
+  /*
+   * Wait for final rebalances and all consumers to settle,
+   * then verify assignments and received message counts.
+   */
+  Test::Say(_C_YEL "Waiting for final assignment state\n");
+  int done_count = 0;
+  /* Allow at least 20 seconds for group to stabilize. */
+  int64_t stabilize_until = test_clock() + (20 * 1000 * 1000); /* 20s */
+
+  while (done_count < 2) {
+    bool stabilized = test_clock() > stabilize_until;
+
+    poll_all_consumers(consumers, rebalance_cbs, N_CONSUMERS, 5000);
+
+    /* Verify consumer assignments */
+    int counts[N_CONSUMERS];
+    map<Toppar, RdKafka::KafkaConsumer *> all_assignments;
+    Test::Say(tostr() << "Consumer assignments "
+                      << "(subscription_variation " << subscription_variation
+                      << ")" << (stabilized ? " (stabilized)" : "")
+                      << (use_rebalance_cb ? " (use_rebalance_cb)"
+                                           : " (no rebalance cb)")
+                      << ":\n");
+    for (int i = 0; i < N_CONSUMERS; i++) {
+      bool last_rebalance_stabilized =
+          stabilized &&
+          (!use_rebalance_cb ||
+           /* session.timeout.ms * 2 + 1 */
+           test_clock() > rebalance_cbs[i].ts_last_assign + (13 * 1000 * 1000));
+
+      counts[i] = verify_consumer_assignment(
+          consumers[i], rebalance_cbs[i], consumer_topics[i],
+          /* allow empty */
+          true,
+          /* if we're waiting for a
+           * rebalance it is okay for the
+           * current assignment to contain
+           * topics that this consumer
+           * (no longer) subscribes to. */
+          !last_rebalance_stabilized || !use_rebalance_cb ||
+              rebalance_cbs[i].wait_rebalance,
+          /* do not allow assignments for
+           * topics that are not subscribed*/
+          &all_assignments,
+          /* Verify received message counts
+           * once the assignments have
+           * stabilized.
+           * Requires the rebalance cb.*/
+          done_count > 0 && use_rebalance_cb ? N_MSGS_PER_PARTITION : -1);
+    }
+
+    Test::Say(tostr() << all_assignments.size() << "/" << N_PARTITIONS
+                      << " partitions assigned\n");
+
+    bool done = true;
+    for (int i = 0; i < N_CONSUMERS; i++) {
+      /* For each topic the consumer subscribes to it should
+       * be assigned its share of partitions. */
+      int exp_parts = 0;
+      for (vector<string>::const_iterator it = consumer_topics[i].begin();
+           it != consumer_topics[i].end(); it++)
+        exp_parts += N_PARTS_PER_TOPIC / (int)topic_consumers[*it].size();
+
+      Test::Say(tostr() << (counts[i] == exp_parts ? "" : _C_YEL) << "Consumer "
+                        << consumers[i]->name() << " has " << counts[i]
+                        << " assigned partitions (" << consumer_topics[i].size()
+                        << " subscribed topic(s))"
+                        << ", expecting " << exp_parts
+                        << " assigned partitions\n");
+
+      if (counts[i] != exp_parts)
+        done = false;
+    }
+
+    if (done && stabilized) {
+      done_count++;
+      Test::Say(tostr() << "All assignments verified, done count is "
+                        << done_count << "\n");
+    }
+  }
+
+  Test::Say("Disposing consumers\n");
+  for (int i = 0; i < N_CONSUMERS; i++) {
+    TEST_ASSERT(!use_rebalance_cb || !rebalance_cbs[i].wait_rebalance,
+                "Consumer %d still waiting for rebalance", i);
+    if (i & 1)
+      consumers[i]->close();
+    delete consumers[i];
+  }
+
+  SUB_TEST_PASS();
+}
+
+
+
+extern "C" {
+
+static int rebalance_cnt;
+static rd_kafka_resp_err_t rebalance_exp_event;
+static rd_bool_t rebalance_exp_lost;
+
+extern void test_print_partition_list(
+    const rd_kafka_topic_partition_list_t *partitions);
+
+
+static void rebalance_cb(rd_kafka_t *rk,
+                         rd_kafka_resp_err_t err,
+                         rd_kafka_topic_partition_list_t *parts,
+                         void *opaque) {
+  rebalance_cnt++;
+  TEST_SAY("Rebalance #%d: %s: %d partition(s)\n", rebalance_cnt,
+           rd_kafka_err2name(err), parts->cnt);
+
+  test_print_partition_list(parts);
+
+  TEST_ASSERT(err == rebalance_exp_event ||
+                  rebalance_exp_event == RD_KAFKA_RESP_ERR_NO_ERROR,
+              "Expected rebalance event %s, not %s",
+              rd_kafka_err2name(rebalance_exp_event), rd_kafka_err2name(err));
+
+  if (rebalance_exp_lost) {
+    TEST_ASSERT(rd_kafka_assignment_lost(rk), "Expected partitions lost");
+    TEST_SAY("Partitions were lost\n");
+  }
+
+  if (err == RD_KAFKA_RESP_ERR__ASSIGN_PARTITIONS) {
+    test_consumer_incremental_assign("assign", rk, parts);
+  } else {
+    test_consumer_incremental_unassign("unassign", rk, parts);
+  }
+}
+
+/**
+ * @brief Wait for an expected rebalance event, or fail.
+ */
+static void expect_rebalance0(const char *func,
+                              int line,
+                              const char *what,
+                              rd_kafka_t *c,
+                              rd_kafka_resp_err_t exp_event,
+                              rd_bool_t exp_lost,
+                              int timeout_s) {
+  int64_t tmout = test_clock() + (timeout_s * 1000000);
+  int start_cnt = rebalance_cnt;
+
+  TEST_SAY("%s:%d: Waiting for %s (%s) for %ds\n", func, line, what,
+           rd_kafka_err2name(exp_event), timeout_s);
+
+  rebalance_exp_lost  = exp_lost;
+  rebalance_exp_event = exp_event;
+
+  while (tmout > test_clock() && rebalance_cnt == start_cnt) {
+    test_consumer_poll_once(c, NULL, 1000);
+  }
+
+  if (rebalance_cnt == start_cnt + 1) {
+    rebalance_exp_event = RD_KAFKA_RESP_ERR_NO_ERROR;
+    rebalance_exp_lost = exp_lost = rd_false;
+    return;
+  }
+
+  TEST_FAIL("%s:%d: Timed out waiting for %s (%s)", func, line, what,
+            rd_kafka_err2name(exp_event));
+}
+
+#define expect_rebalance(WHAT, C, EXP_EVENT, EXP_LOST, TIMEOUT_S)              \
+  expect_rebalance0(__FUNCTION__, __LINE__, WHAT, C, EXP_EVENT, EXP_LOST,      \
+                    TIMEOUT_S)
+
+
+/* Check lost partitions revoke occurs on ILLEGAL_GENERATION heartbeat error.
+ */
+
+static void p_lost_partitions_heartbeat_illegal_generation_test() {
+  const char *bootstraps;
+  rd_kafka_mock_cluster_t *mcluster;
+  const char *groupid = "mygroup";
+  const char *topic   = "test";
+  rd_kafka_t *c;
+  rd_kafka_conf_t *conf;
+
+  SUB_TEST_QUICK();
+
+  mcluster = test_mock_cluster_new(3, &bootstraps);
+
+  rd_kafka_mock_coordinator_set(mcluster, "group", groupid, 1);
+
+  /* Seed the topic with messages */
+  test_produce_msgs_easy_v(topic, 0, 0, 0, 100, 10, "bootstrap.servers",
+                           bootstraps, "batch.num.messages", "10",
+                           "security.protocol", "plaintext", NULL);
+
+  test_conf_init(&conf, NULL, 30);
+  test_conf_set(conf, "bootstrap.servers", bootstraps);
+  test_conf_set(conf, "security.protocol", "PLAINTEXT");
+  test_conf_set(conf, "group.id", groupid);
+  test_conf_set(conf, "session.timeout.ms", "5000");
+  test_conf_set(conf, "heartbeat.interval.ms", "1000");
+  test_conf_set(conf, "auto.offset.reset", "earliest");
+  test_conf_set(conf, "enable.auto.commit", "false");
+  test_conf_set(conf, "partition.assignment.strategy", "cooperative-sticky");
+
+  c = test_create_consumer(groupid, rebalance_cb, conf, NULL);
+
+  test_consumer_subscribe(c, topic);
+
+  expect_rebalance("initial assignment", c,
+                   RD_KAFKA_RESP_ERR__ASSIGN_PARTITIONS,
+                   rd_false /*don't expect lost*/, 5 + 2);
+
+  /* Fail heartbeats */
+  rd_kafka_mock_push_request_errors(mcluster, RD_KAFKAP_Heartbeat, 5,
+                                    RD_KAFKA_RESP_ERR_ILLEGAL_GENERATION,
+                                    RD_KAFKA_RESP_ERR_ILLEGAL_GENERATION,
+                                    RD_KAFKA_RESP_ERR_ILLEGAL_GENERATION,
+                                    RD_KAFKA_RESP_ERR_ILLEGAL_GENERATION,
+                                    RD_KAFKA_RESP_ERR_ILLEGAL_GENERATION);
+
+  expect_rebalance("lost partitions", c, RD_KAFKA_RESP_ERR__REVOKE_PARTITIONS,
+                   rd_true /*expect lost*/, 10 + 2);
+
+  rd_kafka_mock_clear_request_errors(mcluster, RD_KAFKAP_Heartbeat);
+
+  expect_rebalance("rejoin after lost", c, RD_KAFKA_RESP_ERR__ASSIGN_PARTITIONS,
+                   rd_false /*don't expect lost*/, 10 + 2);
+
+  TEST_SAY("Closing consumer\n");
+  test_consumer_close(c);
+
+  TEST_SAY("Destroying consumer\n");
+  rd_kafka_destroy(c);
+
+  TEST_SAY("Destroying mock cluster\n");
+  test_mock_cluster_destroy(mcluster);
+
+  SUB_TEST_PASS();
+}
+
+
+
+/* Check lost partitions revoke occurs on ILLEGAL_GENERATION JoinGroup
+ * or SyncGroup error.
+ */
+
+static void q_lost_partitions_illegal_generation_test(
+    rd_bool_t test_joingroup_fail) {
+  const char *bootstraps;
+  rd_kafka_mock_cluster_t *mcluster;
+  const char *groupid = "mygroup";
+  const char *topic1  = "test1";
+  const char *topic2  = "test2";
+  rd_kafka_t *c;
+  rd_kafka_conf_t *conf;
+  rd_kafka_resp_err_t err;
+  rd_kafka_topic_partition_list_t *topics;
+
+  SUB_TEST0(!test_joingroup_fail /*quick*/, "test_joingroup_fail=%d",
+            test_joingroup_fail);
+
+  mcluster = test_mock_cluster_new(3, &bootstraps);
+
+  rd_kafka_mock_coordinator_set(mcluster, "group", groupid, 1);
+
+  /* Seed the topic1 with messages */
+  test_produce_msgs_easy_v(topic1, 0, 0, 0, 100, 10, "bootstrap.servers",
+                           bootstraps, "batch.num.messages", "10",
+                           "security.protocol", "plaintext", NULL);
+
+  /* Seed the topic2 with messages */
+  test_produce_msgs_easy_v(topic2, 0, 0, 0, 100, 10, "bootstrap.servers",
+                           bootstraps, "batch.num.messages", "10",
+                           "security.protocol", "plaintext", NULL);
+
+  test_conf_init(&conf, NULL, 30);
+  test_conf_set(conf, "bootstrap.servers", bootstraps);
+  test_conf_set(conf, "security.protocol", "PLAINTEXT");
+  test_conf_set(conf, "group.id", groupid);
+  test_conf_set(conf, "session.timeout.ms", "5000");
+  test_conf_set(conf, "heartbeat.interval.ms", "1000");
+  test_conf_set(conf, "auto.offset.reset", "earliest");
+  test_conf_set(conf, "enable.auto.commit", "false");
+  test_conf_set(conf, "partition.assignment.strategy", "cooperative-sticky");
+
+  c = test_create_consumer(groupid, rebalance_cb, conf, NULL);
+
+  test_consumer_subscribe(c, topic1);
+
+  expect_rebalance("initial assignment", c,
+                   RD_KAFKA_RESP_ERR__ASSIGN_PARTITIONS,
+                   rd_false /*don't expect lost*/, 5 + 2);
+
+  /* Fail JoinGroups or SyncGroups */
+  rd_kafka_mock_push_request_errors(
+      mcluster, test_joingroup_fail ? RD_KAFKAP_JoinGroup : RD_KAFKAP_SyncGroup,
+      5, RD_KAFKA_RESP_ERR_ILLEGAL_GENERATION,
+      RD_KAFKA_RESP_ERR_ILLEGAL_GENERATION,
+      RD_KAFKA_RESP_ERR_ILLEGAL_GENERATION,
+      RD_KAFKA_RESP_ERR_ILLEGAL_GENERATION,
+      RD_KAFKA_RESP_ERR_ILLEGAL_GENERATION);
+
+  topics = rd_kafka_topic_partition_list_new(2);
+  rd_kafka_topic_partition_list_add(topics, topic1, RD_KAFKA_PARTITION_UA);
+  rd_kafka_topic_partition_list_add(topics, topic2, RD_KAFKA_PARTITION_UA);
+  err = rd_kafka_subscribe(c, topics);
+  if (err)
+    TEST_FAIL("%s: Failed to subscribe to topics: %s\n", rd_kafka_name(c),
+              rd_kafka_err2str(err));
+  rd_kafka_topic_partition_list_destroy(topics);
+
+  expect_rebalance("lost partitions", c, RD_KAFKA_RESP_ERR__REVOKE_PARTITIONS,
+                   rd_true /*expect lost*/, 10 + 2);
+
+  rd_kafka_mock_clear_request_errors(mcluster, test_joingroup_fail
+                                                   ? RD_KAFKAP_JoinGroup
+                                                   : RD_KAFKAP_SyncGroup);
+
+  expect_rebalance("rejoin group", c, RD_KAFKA_RESP_ERR__ASSIGN_PARTITIONS,
+                   rd_false /*expect lost*/, 10 + 2);
+
+  TEST_SAY("Closing consumer\n");
+  test_consumer_close(c);
+
+  TEST_SAY("Destroying consumer\n");
+  rd_kafka_destroy(c);
+
+  TEST_SAY("Destroying mock cluster\n");
+  test_mock_cluster_destroy(mcluster);
+
+  SUB_TEST_PASS();
+}
+
+
+
+/* Check lost partitions revoke occurs on ILLEGAL_GENERATION Commit
+ * error.
+ */
+
+static void r_lost_partitions_commit_illegal_generation_test_local() {
+  const char *bootstraps;
+  rd_kafka_mock_cluster_t *mcluster;
+  const char *groupid = "mygroup";
+  const char *topic   = "test";
+  const int msgcnt    = 100;
+  rd_kafka_t *c;
+  rd_kafka_conf_t *conf;
+
+  SUB_TEST();
+
+  mcluster = test_mock_cluster_new(3, &bootstraps);
+
+  rd_kafka_mock_coordinator_set(mcluster, "group", groupid, 1);
+
+  /* Seed the topic with messages */
+  test_produce_msgs_easy_v(topic, 0, 0, 0, msgcnt, 10, "bootstrap.servers",
+                           bootstraps, "batch.num.messages", "10",
+                           "security.protocol", "plaintext", NULL);
+
+  test_conf_init(&conf, NULL, 30);
+  test_conf_set(conf, "bootstrap.servers", bootstraps);
+  test_conf_set(conf, "security.protocol", "PLAINTEXT");
+  test_conf_set(conf, "group.id", groupid);
+  test_conf_set(conf, "auto.offset.reset", "earliest");
+  test_conf_set(conf, "enable.auto.commit", "false");
+  test_conf_set(conf, "partition.assignment.strategy", "cooperative-sticky");
+
+  c = test_create_consumer(groupid, rebalance_cb, conf, NULL);
+
+  test_consumer_subscribe(c, topic);
+
+  expect_rebalance("initial assignment", c,
+                   RD_KAFKA_RESP_ERR__ASSIGN_PARTITIONS,
+                   rd_false /*don't expect lost*/, 5 + 2);
+
+
+  /* Consume some messages so that the commit has something to commit. */
+  test_consumer_poll("consume", c, -1, -1, -1, msgcnt / 2, NULL);
+
+  /* Fail Commit */
+  rd_kafka_mock_push_request_errors(mcluster, RD_KAFKAP_OffsetCommit, 5,
+                                    RD_KAFKA_RESP_ERR_ILLEGAL_GENERATION,
+                                    RD_KAFKA_RESP_ERR_ILLEGAL_GENERATION,
+                                    RD_KAFKA_RESP_ERR_ILLEGAL_GENERATION,
+                                    RD_KAFKA_RESP_ERR_ILLEGAL_GENERATION,
+                                    RD_KAFKA_RESP_ERR_ILLEGAL_GENERATION);
+
+  rd_kafka_commit(c, NULL, rd_false);
+
+  expect_rebalance("lost partitions", c, RD_KAFKA_RESP_ERR__REVOKE_PARTITIONS,
+                   rd_true /*expect lost*/, 10 + 2);
+
+  expect_rebalance("rejoin group", c, RD_KAFKA_RESP_ERR__ASSIGN_PARTITIONS,
+                   rd_false /*expect lost*/, 20 + 2);
+
+  TEST_SAY("Closing consumer\n");
+  test_consumer_close(c);
+
+  TEST_SAY("Destroying consumer\n");
+  rd_kafka_destroy(c);
+
+  TEST_SAY("Destroying mock cluster\n");
+  test_mock_cluster_destroy(mcluster);
+}
+
+
+/**
+ * @brief Rebalance callback for the v_.. test below.
+ */
+static void v_rebalance_cb(rd_kafka_t *rk,
+                           rd_kafka_resp_err_t err,
+                           rd_kafka_topic_partition_list_t *parts,
+                           void *opaque) {
+  bool *auto_commitp = (bool *)opaque;
+
+  TEST_SAY("%s: %s: %d partition(s)%s\n", rd_kafka_name(rk),
+           rd_kafka_err2name(err), parts->cnt,
+           rd_kafka_assignment_lost(rk) ? " - assignment lost" : "");
+
+  test_print_partition_list(parts);
+
+  if (err == RD_KAFKA_RESP_ERR__ASSIGN_PARTITIONS) {
+    test_consumer_incremental_assign("assign", rk, parts);
+  } else {
+    test_consumer_incremental_unassign("unassign", rk, parts);
+
+    if (!*auto_commitp) {
+      rd_kafka_resp_err_t commit_err;
+
+      TEST_SAY("Attempting manual commit after unassign, in 2 seconds..\n");
+      /* Sleep enough to have the generation-id bumped by rejoin. */
+      rd_sleep(2);
+      commit_err = rd_kafka_commit(rk, NULL, 0 /*sync*/);
+      TEST_ASSERT(!commit_err || commit_err == RD_KAFKA_RESP_ERR__NO_OFFSET ||
+                      commit_err == RD_KAFKA_RESP_ERR__DESTROY,
+                  "%s: manual commit failed: %s", rd_kafka_name(rk),
+                  rd_kafka_err2str(commit_err));
+    }
+  }
+}
+
+/**
+ * @brief Commit callback for the v_.. test.
+ */
+static void v_commit_cb(rd_kafka_t *rk,
+                        rd_kafka_resp_err_t err,
+                        rd_kafka_topic_partition_list_t *offsets,
+                        void *opaque) {
+  TEST_SAY("%s offset commit for %d offsets: %s\n", rd_kafka_name(rk),
+           offsets ? offsets->cnt : -1, rd_kafka_err2name(err));
+  TEST_ASSERT(!err || err == RD_KAFKA_RESP_ERR__NO_OFFSET ||
+                  err == RD_KAFKA_RESP_ERR__DESTROY /* consumer was closed */,
+              "%s offset commit failed: %s", rd_kafka_name(rk),
+              rd_kafka_err2str(err));
+}
+
+
+static void v_commit_during_rebalance(bool with_rebalance_cb,
+                                      bool auto_commit) {
+  rd_kafka_t *p, *c1, *c2;
+  rd_kafka_conf_t *conf;
+  const char *topic              = test_mk_topic_name("0113_v", 1);
+  const int partition_cnt        = 6;
+  const int msgcnt_per_partition = 100;
+  const int msgcnt               = partition_cnt * msgcnt_per_partition;
+  uint64_t testid;
+  int i;
+
+
+  SUB_TEST("With%s rebalance callback and %s-commit",
+           with_rebalance_cb ? "" : "out", auto_commit ? "auto" : "manual");
+
+  test_conf_init(&conf, NULL, 30);
+  testid = test_id_generate();
+
+  /*
+   * Produce messages to topic
+   */
+  p = test_create_producer();
+
+  test_create_topic(p, topic, partition_cnt, 1);
+
+  for (i = 0; i < partition_cnt; i++) {
+    test_produce_msgs2(p, topic, testid, i, i * msgcnt_per_partition,
+                       msgcnt_per_partition, NULL, 0);
+  }
+
+  test_flush(p, -1);
+
+  rd_kafka_destroy(p);
+
+
+  test_conf_set(conf, "auto.offset.reset", "earliest");
+  test_conf_set(conf, "enable.auto.commit", auto_commit ? "true" : "false");
+  test_conf_set(conf, "partition.assignment.strategy", "cooperative-sticky");
+  rd_kafka_conf_set_offset_commit_cb(conf, v_commit_cb);
+  rd_kafka_conf_set_opaque(conf, (void *)&auto_commit);
+
+  TEST_SAY("Create and subscribe first consumer\n");
+  c1 = test_create_consumer(topic, with_rebalance_cb ? v_rebalance_cb : NULL,
+                            rd_kafka_conf_dup(conf), NULL);
+  TEST_ASSERT(rd_kafka_opaque(c1) == (void *)&auto_commit,
+              "c1 opaque mismatch");
+  test_consumer_subscribe(c1, topic);
+
+  /* Consume some messages so that we know we have an assignment
+   * and something to commit. */
+  test_consumer_poll("C1.PRECONSUME", c1, testid, -1, 0,
+                     msgcnt / partition_cnt / 2, NULL);
+
+  TEST_SAY("Create and subscribe second consumer\n");
+  c2 = test_create_consumer(topic, with_rebalance_cb ? v_rebalance_cb : NULL,
+                            conf, NULL);
+  TEST_ASSERT(rd_kafka_opaque(c2) == (void *)&auto_commit,
+              "c2 opaque mismatch");
+  test_consumer_subscribe(c2, topic);
+
+  /* Poll both consumers */
+  for (i = 0; i < 10; i++) {
+    test_consumer_poll_once(c1, NULL, 1000);
+    test_consumer_poll_once(c2, NULL, 1000);
+  }
+
+  TEST_SAY("Closing consumers\n");
+  test_consumer_close(c1);
+  test_consumer_close(c2);
+
+  rd_kafka_destroy(c1);
+  rd_kafka_destroy(c2);
+
+  SUB_TEST_PASS();
+}
+
+
+/**
+ * @brief Verify that incremental rebalances retain stickyness.
+ */
+static void x_incremental_rebalances(void) {
+#define _NUM_CONS 3
+  rd_kafka_t *c[_NUM_CONS];
+  rd_kafka_conf_t *conf;
+  const char *topic = test_mk_topic_name("0113_x", 1);
+  int i;
+
+  SUB_TEST();
+  test_conf_init(&conf, NULL, 60);
+
+  test_create_topic(NULL, topic, 6, 1);
+
+  test_conf_set(conf, "partition.assignment.strategy", "cooperative-sticky");
+  for (i = 0; i < _NUM_CONS; i++) {
+    char clientid[32];
+    rd_snprintf(clientid, sizeof(clientid), "consumer%d", i);
+    test_conf_set(conf, "client.id", clientid);
+
+    c[i] = test_create_consumer(topic, NULL, rd_kafka_conf_dup(conf), NULL);
+  }
+  rd_kafka_conf_destroy(conf);
+
+  /* First consumer joins group */
+  TEST_SAY("%s: joining\n", rd_kafka_name(c[0]));
+  test_consumer_subscribe(c[0], topic);
+  test_consumer_wait_assignment(c[0], rd_true /*poll*/);
+  test_consumer_verify_assignment(c[0], rd_true /*fail immediately*/, topic, 0,
+                                  topic, 1, topic, 2, topic, 3, topic, 4, topic,
+                                  5, NULL);
+
+
+  /* Second consumer joins group */
+  TEST_SAY("%s: joining\n", rd_kafka_name(c[1]));
+  test_consumer_subscribe(c[1], topic);
+  test_consumer_wait_assignment(c[1], rd_true /*poll*/);
+  rd_sleep(3);
+  test_consumer_verify_assignment(c[0], rd_false /*fail later*/, topic, 3,
+                                  topic, 4, topic, 5, NULL);
+  test_consumer_verify_assignment(c[1], rd_false /*fail later*/, topic, 0,
+                                  topic, 1, topic, 2, NULL);
+
+  /* Third consumer joins group */
+  TEST_SAY("%s: joining\n", rd_kafka_name(c[2]));
+  test_consumer_subscribe(c[2], topic);
+  test_consumer_wait_assignment(c[2], rd_true /*poll*/);
+  rd_sleep(3);
+  test_consumer_verify_assignment(c[0], rd_false /*fail later*/, topic, 4,
+                                  topic, 5, NULL);
+  test_consumer_verify_assignment(c[1], rd_false /*fail later*/, topic, 1,
+                                  topic, 2, NULL);
+  test_consumer_verify_assignment(c[2], rd_false /*fail later*/, topic, 3,
+                                  topic, 0, NULL);
+
+  /* Raise any previously failed verify_assignment calls and fail the test */
+  TEST_LATER_CHECK();
+
+  for (i = 0; i < _NUM_CONS; i++)
+    rd_kafka_destroy(c[i]);
+
+  SUB_TEST_PASS();
+
+#undef _NUM_CONS
+}
+
+/* Local tests not needing a cluster */
+int main_0113_cooperative_rebalance_local(int argc, char **argv) {
+  a_assign_rapid();
+  p_lost_partitions_heartbeat_illegal_generation_test();
+  q_lost_partitions_illegal_generation_test(rd_false /*joingroup*/);
+  q_lost_partitions_illegal_generation_test(rd_true /*syncgroup*/);
+  r_lost_partitions_commit_illegal_generation_test_local();
+  return 0;
+}
+
+int main_0113_cooperative_rebalance(int argc, char **argv) {
+  int i;
+
+  a_assign_tests();
+  b_subscribe_with_cb_test(true /*close consumer*/);
+  b_subscribe_with_cb_test(false /*don't close consumer*/);
+  c_subscribe_no_cb_test(true /*close consumer*/);
+
+  if (test_quick) {
+    Test::Say("Skipping tests >= c_ .. due to quick mode\n");
+    return 0;
+  }
+
+  c_subscribe_no_cb_test(false /*don't close consumer*/);
+  d_change_subscription_add_topic(true /*close consumer*/);
+  d_change_subscription_add_topic(false /*don't close consumer*/);
+  e_change_subscription_remove_topic(true /*close consumer*/);
+  e_change_subscription_remove_topic(false /*don't close consumer*/);
+  f_assign_call_cooperative();
+  g_incremental_assign_call_eager();
+  h_delete_topic();
+  i_delete_topic_2();
+  j_delete_topic_no_rb_callback();
+  k_add_partition();
+  l_unsubscribe();
+  m_unsubscribe_2();
+  n_wildcard();
+  o_java_interop();
+  for (i = 1; i <= 6; i++) /* iterate over 6 different test variations */
+    s_subscribe_when_rebalancing(i);
+  for (i = 1; i <= 2; i++)
+    t_max_poll_interval_exceeded(i);
+  /* Run all 2*3 variations of the u_.. test */
+  for (i = 0; i < 3; i++) {
+    u_multiple_subscription_changes(true /*with rebalance_cb*/, i);
+    u_multiple_subscription_changes(false /*without rebalance_cb*/, i);
+  }
+  v_commit_during_rebalance(true /*with rebalance callback*/,
+                            true /*auto commit*/);
+  v_commit_during_rebalance(false /*without rebalance callback*/,
+                            true /*auto commit*/);
+  v_commit_during_rebalance(true /*with rebalance callback*/,
+                            false /*manual commit*/);
+  x_incremental_rebalances();
+
+  return 0;
+}
+}