Changed test to ensure that PositionResetException is thrown

Changed the test to wait for the queue to reach capacity before
restarting the PrefetchRecordsPublisher.  This should mostly ensure
that calling restartFrom will trigger a throw of a
PositionResetException.

Added @VisibleFortest on the queue since it was already being used in testing.

amazon-kinesis-client/src/main/java/software/amazon/kinesis/retrieval/polling/PrefetchRecordsPublisher.java

@@ -25,6 +25,7 @@
 import java.util.concurrent.locks.ReentrantReadWriteLock;
 import java.util.stream.Collectors;
 
+import com.google.common.annotations.VisibleForTesting;
 import org.apache.commons.lang3.Validate;
 import org.reactivestreams.Subscriber;
 import org.reactivestreams.Subscription;
@@ -63,6 +64,7 @@
 @KinesisClientInternalApi
 public class PrefetchRecordsPublisher implements RecordsPublisher {
  private static final String EXPIRED_ITERATOR_METRIC = "ExpiredIterator";
+ @VisibleForTesting
  LinkedBlockingQueue<PrefetchRecordsRetrieved> getRecordsResultQueue;
  private int maxPendingProcessRecordsInput;
  private int maxByteSize;

amazon-kinesis-client/src/test/java/software/amazon/kinesis/retrieval/polling/PrefetchRecordsPublisherTest.java

@@ -365,6 +365,10 @@ public void testResetClearsRemainingData() {
 
  verify(getRecordsRetrievalStrategy, atLeast(2)).getRecords(anyInt());
 
+ while(getRecordsCache.getRecordsResultQueue.remainingCapacity() > 0) {
+ Thread.yield();
+ }
+
  getRecordsCache.restartFrom(lastProcessed);
  RecordsRetrieved postRestart = getRecordsCache.getNextResult();