diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/RetryOnInvalidatedSessionTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/RetryOnInvalidatedSessionTest.java
index aaceca5491..ae6f6d2442 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/RetryOnInvalidatedSessionTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/RetryOnInvalidatedSessionTest.java
@@ -39,6 +39,7 @@
 import com.google.common.base.Stopwatch;
 import com.google.common.util.concurrent.MoreExecutors;
 import com.google.protobuf.ListValue;
+import com.google.spanner.v1.DeleteSessionRequest;
 import com.google.spanner.v1.ResultSetMetadata;
 import com.google.spanner.v1.StructType;
 import com.google.spanner.v1.StructType.Field;
@@ -269,6 +270,7 @@ private static void invalidateSessionPool(DatabaseClient client, int minSessions
         spannerClient.listSessions("projects/[PROJECT]/instances/[INSTANCE]/databases/[DATABASE]");
     for (com.google.spanner.v1.Session session : response.iterateAll()) {
       spannerClient.deleteSession(session.getName());
+      mockSpanner.doDeleteSession(session);
     }
   }