MINOR: Test assign() and assignment() in the integration test

clients/src/main/java/org/apache/kafka/clients/consumer/internals/NetworkClientDelegate.java

@@ -236,7 +236,12 @@ AbstractRequest.Builder<?> requestBuilder() {
 
         @Override
         public String toString() {
-            return "UnsentRequest(builder=" + requestBuilder + ")";
+            return "UnsentRequest{" +
+                    "requestBuilder=" + requestBuilder +
+                    ", handler=" + handler +
+                    ", node=" + node +
+                    ", timer=" + timer +
+                    '}';
         }
     }
 

clients/src/main/java/org/apache/kafka/clients/consumer/internals/PrototypeAsyncConsumer.java

@@ -333,7 +333,7 @@ public Map<TopicPartition, OffsetAndMetadata> committed(final Set<TopicPartition
         final OffsetFetchApplicationEvent event = new OffsetFetchApplicationEvent(partitions);
         eventHandler.add(event);
         try {
-            return event.complete(Duration.ofMillis(100));
+            return event.complete(timeout);
         } catch (InterruptedException e) {
             throw new InterruptException(e);
         } catch (TimeoutException e) {

core/src/test/scala/integration/kafka/api/BaseAsyncConsumerTest.scala

@@ -17,8 +17,10 @@
 package kafka.api
 
 import kafka.utils.TestUtils.waitUntilTrue
+import org.junit.jupiter.api.Assertions.assertTrue
 import org.junit.jupiter.api.Test
 
+import scala.jdk.CollectionConverters._
 
 class BaseAsyncConsumerTest extends AbstractConsumerTest {
   @Test
@@ -29,10 +31,12 @@ class BaseAsyncConsumerTest extends AbstractConsumerTest {
     val startingTimestamp = System.currentTimeMillis()
     val cb = new CountConsumerCommitCallback
     sendRecords(producer, numRecords, tp, startingTimestamp = startingTimestamp)
+    consumer.assign(List(tp).asJava)
     consumer.commitAsync(cb)
     waitUntilTrue(() => {
       cb.successCount == 1
     }, "wait until commit is completed successfully", 5000)
+    assertTrue(consumer.assignment.contains(tp))
   }
 
   @Test
@@ -42,6 +46,9 @@ class BaseAsyncConsumerTest extends AbstractConsumerTest {
     val numRecords = 10000
     val startingTimestamp = System.currentTimeMillis()
     sendRecords(producer, numRecords, tp, startingTimestamp = startingTimestamp)
+    consumer.assign(List(tp).asJava)
     consumer.commitSync();
+
+    assertTrue(consumer.assignment.contains(tp))
   }
 }