diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/XGoogSpannerRequestId.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/XGoogSpannerRequestId.java
index 274592f9b4..1a81679c5e 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/XGoogSpannerRequestId.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/XGoogSpannerRequestId.java
@@ -199,4 +199,10 @@ XGoogSpannerRequestId withNthClientId(long replacementClientId) {
     return XGoogSpannerRequestId.of(
         replacementClientId, this.nthChannelId, this.nthRequest, this.attempt);
   }
+
+  @VisibleForTesting
+  XGoogSpannerRequestId withAttempt(long replacementAttempt) {
+    return XGoogSpannerRequestId.of(
+        this.nthClientId, this.nthChannelId, this.nthRequest, replacementAttempt);
+  }
 }
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/DatabaseClientImplTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/DatabaseClientImplTest.java
index fa8b5c982f..f4b70e86b4 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/DatabaseClientImplTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/DatabaseClientImplTest.java
@@ -1417,8 +1417,7 @@ public void testWriteAtLeastOnceAborted() {
 
     List<CommitRequest> commitRequests = mockSpanner.getRequestsOfType(CommitRequest.class);
     assertEquals(2, commitRequests.size());
-    // TODO(@odeke-em): Enable in later PR.
-    // xGoogReqIdInterceptor.assertIntegrity();
+    xGoogReqIdInterceptor.assertIntegrity();
   }
 
   @Test
@@ -2910,34 +2909,34 @@ public void testPartitionedDmlDoesNotTimeout() {
 
       DatabaseClientImpl dbImpl = ((DatabaseClientImpl) client);
       int channelId = 0;
-      try (Session session = dbImpl.getSession()) {
-        channelId = ((PooledSessionFuture) session).getChannel();
+      try (PooledSessionFuture session = dbImpl.getSession()) {
+        channelId = session.getChannel();
       }
       int dbId = dbImpl.dbId;
       long NON_DETERMINISTIC = XGoogSpannerRequestIdTest.NON_DETERMINISTIC;
       XGoogSpannerRequestIdTest.MethodAndRequestId[] wantStreamingValues = {
         XGoogSpannerRequestIdTest.ofMethodAndRequestId(
             "google.spanner.v1.Spanner/ExecuteStreamingSql",
-            new XGoogSpannerRequestId(NON_DETERMINISTIC, channelId, 6, 1)),
+            new XGoogSpannerRequestId(
+                NON_DETERMINISTIC, NON_DETERMINISTIC, NON_DETERMINISTIC, NON_DETERMINISTIC)),
       };
-      if (false) { // TODO(@odeke-em): enable in next PRs.
-        xGoogReqIdInterceptor.checkExpectedStreamingXGoogRequestIds(wantStreamingValues);
-      }
+      xGoogReqIdInterceptor.checkExpectedStreamingXGoogRequestIds(wantStreamingValues);
 
       XGoogSpannerRequestIdTest.MethodAndRequestId[] wantUnaryValues = {
         XGoogSpannerRequestIdTest.ofMethodAndRequestId(
             "google.spanner.v1.Spanner/BeginTransaction",
-            new XGoogSpannerRequestId(NON_DETERMINISTIC, channelId, 7, 1)),
+            new XGoogSpannerRequestId(
+                NON_DETERMINISTIC, NON_DETERMINISTIC, NON_DETERMINISTIC, NON_DETERMINISTIC)),
         XGoogSpannerRequestIdTest.ofMethodAndRequestId(
             "google.spanner.v1.Spanner/CreateSession",
-            new XGoogSpannerRequestId(NON_DETERMINISTIC, 0, 1, 1)),
+            new XGoogSpannerRequestId(
+                NON_DETERMINISTIC, NON_DETERMINISTIC, NON_DETERMINISTIC, NON_DETERMINISTIC)),
         XGoogSpannerRequestIdTest.ofMethodAndRequestId(
             "google.spanner.v1.Spanner/ExecuteSql",
-            new XGoogSpannerRequestId(NON_DETERMINISTIC, channelId, 8, 1)),
+            new XGoogSpannerRequestId(
+                NON_DETERMINISTIC, NON_DETERMINISTIC, NON_DETERMINISTIC, NON_DETERMINISTIC)),
       };
-      if (false) { // TODO(@odeke-em): enable in next PRs.
-        xGoogReqIdInterceptor.checkExpectedUnaryXGoogRequestIdsAsSuffixes(wantUnaryValues);
-      }
+      xGoogReqIdInterceptor.checkExpectedUnaryXGoogRequestIdsAsSuffixes(wantUnaryValues);
     }
   }
 
@@ -3023,35 +3022,35 @@ public void testPartitionedDmlWithHigherTimeout() {
 
       DatabaseClientImpl dbImpl = ((DatabaseClientImpl) client);
       int channelId = 0;
-      try (Session session = dbImpl.getSession()) {
-        channelId = ((PooledSessionFuture) session).getChannel();
+      try (PooledSessionFuture session = dbImpl.getSession()) {
+        channelId = session.getChannel();
       }
       int dbId = dbImpl.dbId;
       long NON_DETERMINISTIC = XGoogSpannerRequestIdTest.NON_DETERMINISTIC;
       XGoogSpannerRequestIdTest.MethodAndRequestId[] wantStreamingValues = {
         XGoogSpannerRequestIdTest.ofMethodAndRequestId(
             "google.spanner.v1.Spanner/ExecuteStreamingSql",
-            new XGoogSpannerRequestId(NON_DETERMINISTIC, channelId, 6, 1)),
+            new XGoogSpannerRequestId(
+                NON_DETERMINISTIC, NON_DETERMINISTIC, NON_DETERMINISTIC, NON_DETERMINISTIC)),
       };
 
-      if (false) { // TODO(@odeke-em): enable in next PRs.
-        xGoogReqIdInterceptor.checkExpectedStreamingXGoogRequestIds(wantStreamingValues);
-      }
+      xGoogReqIdInterceptor.checkExpectedStreamingXGoogRequestIds(wantStreamingValues);
 
       XGoogSpannerRequestIdTest.MethodAndRequestId[] wantUnaryValues = {
         XGoogSpannerRequestIdTest.ofMethodAndRequestId(
             "google.spanner.v1.Spanner/BeginTransaction",
-            new XGoogSpannerRequestId(NON_DETERMINISTIC, channelId, 7, 1)),
+            new XGoogSpannerRequestId(
+                NON_DETERMINISTIC, NON_DETERMINISTIC, NON_DETERMINISTIC, NON_DETERMINISTIC)),
         XGoogSpannerRequestIdTest.ofMethodAndRequestId(
             "google.spanner.v1.Spanner/CreateSession",
-            new XGoogSpannerRequestId(NON_DETERMINISTIC, 0, 1, 1)),
+            new XGoogSpannerRequestId(
+                NON_DETERMINISTIC, NON_DETERMINISTIC, NON_DETERMINISTIC, NON_DETERMINISTIC)),
         XGoogSpannerRequestIdTest.ofMethodAndRequestId(
             "google.spanner.v1.Spanner/ExecuteSql",
-            new XGoogSpannerRequestId(NON_DETERMINISTIC, channelId, 8, 1)),
+            new XGoogSpannerRequestId(
+                NON_DETERMINISTIC, NON_DETERMINISTIC, NON_DETERMINISTIC, NON_DETERMINISTIC)),
       };
-      if (false) { // TODO(@odeke-em): enable in next PRs.
-        xGoogReqIdInterceptor.checkExpectedUnaryXGoogRequestIdsAsSuffixes(wantUnaryValues);
-      }
+      xGoogReqIdInterceptor.checkExpectedUnaryXGoogRequestIdsAsSuffixes(wantUnaryValues);
     }
   }
 
@@ -5304,8 +5303,7 @@ public void testSelectHasXGoogRequestIdHeader() {
       assertEquals(1L, resultSet.getLong(0));
       assertFalse(resultSet.next());
     } finally {
-      // TODO(@odeke-em): Enable in later PR.
-      // xGoogReqIdInterceptor.assertIntegrity();
+      xGoogReqIdInterceptor.assertIntegrity();
     }
   }
 
@@ -5394,9 +5392,7 @@ public void testSessionPoolExhaustedError_containsStackTraces() {
             "google.spanner.v1.Spanner/CreateSession",
             new XGoogSpannerRequestId(NON_DETERMINISTIC, 0, 1, 1)),
       };
-      if (false) { // TODO(@odeke-em): enable in next PRs.
-        xGoogReqIdInterceptor.checkExpectedUnaryXGoogRequestIdsAsSuffixes(wantUnaryValues);
-      }
+      xGoogReqIdInterceptor.checkExpectedUnaryXGoogRequestIdsAsSuffixes(wantUnaryValues);
     }
   }
 
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/XGoogSpannerRequestIdTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/XGoogSpannerRequestIdTest.java
index 719b94593b..fb43d8b82a 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/XGoogSpannerRequestIdTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/XGoogSpannerRequestIdTest.java
@@ -73,11 +73,9 @@ public static class ServerHeaderEnforcer implements ServerInterceptor {
     private Set<String> checkMethods;
 
     ServerHeaderEnforcer(Set<String> checkMethods) {
-      this.gotValues = new CopyOnWriteArrayList<String>();
-      this.unaryResults =
-          new ConcurrentHashMap<String, CopyOnWriteArrayList<XGoogSpannerRequestId>>();
-      this.streamingResults =
-          new ConcurrentHashMap<String, CopyOnWriteArrayList<XGoogSpannerRequestId>>();
+      this.gotValues = new CopyOnWriteArrayList<>();
+      this.unaryResults = new ConcurrentHashMap<>();
+      this.streamingResults = new ConcurrentHashMap<>();
       this.checkMethods = checkMethods;
     }
 
@@ -139,6 +137,11 @@ public void assertIntegrity() {
     }
 
     private void assertMonotonicityOfIds(String prefix, List<XGoogSpannerRequestId> reqIds) {
+      reqIds.sort(
+          (id1, id2) -> {
+            if (id1.equals(id2)) return 0;
+            return id1.isGreaterThan(id2) ? 1 : -1;
+          });
       int size = reqIds.size();
 
       List<String> violations = new ArrayList<>();
@@ -161,7 +164,7 @@ private void assertMonotonicityOfIds(String prefix, List<XGoogSpannerRequestId>
     }
 
     public MethodAndRequestId[] accumulatedUnaryValues() {
-      List<MethodAndRequestId> accumulated = new ArrayList();
+      List<MethodAndRequestId> accumulated = new ArrayList<>();
       this.unaryResults.forEach(
           (String method, CopyOnWriteArrayList<XGoogSpannerRequestId> values) -> {
             for (int i = 0; i < values.size(); i++) {
@@ -172,7 +175,7 @@ public MethodAndRequestId[] accumulatedUnaryValues() {
     }
 
     public MethodAndRequestId[] accumulatedStreamingValues() {
-      List<MethodAndRequestId> accumulated = new ArrayList();
+      List<MethodAndRequestId> accumulated = new ArrayList<>();
       this.streamingResults.forEach(
           (String method, CopyOnWriteArrayList<XGoogSpannerRequestId> values) -> {
             for (int i = 0; i < values.size(); i++) {
@@ -308,7 +311,13 @@ static void massageValues(MethodAndRequestId[] mreqs) {
           || mreq.method.compareTo("google.spanner.v1.Spanner/CreateSession") == 0
           || mreq.method.compareTo("google.spanner.v1.Spanner/Commit") == 0) {
         mreqs[i] =
-            new MethodAndRequestId(mreq.method, mreq.requestId.withNthClientId(NON_DETERMINISTIC));
+            new MethodAndRequestId(
+                mreq.method,
+                mreq.requestId
+                    .withNthClientId(NON_DETERMINISTIC)
+                    .withChannelId(NON_DETERMINISTIC)
+                    .withNthRequest(NON_DETERMINISTIC)
+                    .withAttempt(NON_DETERMINISTIC));
       }
     }
   }