test: fail if the same token is seen twice (#983)

olavloite · web-flow · commit 459a47756bec · 2021-03-18T08:14:02.000Z
The backup pagination test should fail if the same page token is returned twice by the backend, instead of fetching the same page indefinitely. Further investigation is necessary if that actually happens, as it is not something that is expected.
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITBackupTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITBackupTest.java
@@ -63,8 +63,9 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.List;
-import java.util.Random;
+import java.util.Set;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
@@ -100,7 +101,6 @@ public class ITBackupTest {
   private RemoteSpannerHelper testHelper;
   private List<String> databases = new ArrayList<>();
   private List<String> backups = new ArrayList<>();
-  private final Random random = new Random();
   private String projectId;
   private String instanceId;
 
@@ -580,8 +580,15 @@ private void testPagination(int expectedMinimumTotalBackups) {
     assertThat(page.getValues()).hasSize(1);
     numBackups++;
     assertThat(page.hasNextPage()).isTrue();
+    Set<String> seenPageTokens = new HashSet<>();
+    seenPageTokens.add("");
     while (page.hasNextPage()) {
-      logger.info(String.format("Fetching page %d", numBackups + 1));
+      logger.info(
+          String.format(
+              "Fetching page %d with page token %s", numBackups + 1, page.getNextPageToken()));
+      // The backend should not return the same page token twice.
+      assertThat(seenPageTokens).doesNotContain(page.getNextPageToken());
+      seenPageTokens.add(page.getNextPageToken());
       page =
           dbAdminClient.listBackups(
               instanceId, Options.pageToken(page.getNextPageToken()), Options.pageSize(1));
