Add some checks to debug test flakiness..

Author: Jerjou Cheng

spanner/cloud-client/src/main/java/com/example/spanner/SpannerSample.java

@@ -24,6 +24,7 @@
 import com.google.cloud.spanner.DatabaseAdminClient;
 import com.google.cloud.spanner.DatabaseClient;
 import com.google.cloud.spanner.DatabaseId;
+import com.google.cloud.spanner.DatabaseInfo;
 // [START transaction_import]
 import com.google.cloud.spanner.Key;
 // [END transaction_import]
@@ -57,6 +58,8 @@
 // [END write_import]
 import java.util.Arrays;
 import java.util.List;
+import com.google.cloud.WaitForOption;
+import java.util.concurrent.TimeUnit;
 
 /**
  * Example code for using the Cloud Spanner API. This example demonstrates all the common
@@ -132,8 +135,15 @@ static void createDatabase(DatabaseAdminClient dbAdminClient, DatabaseId id) {
                         + "  AlbumTitle   STRING(MAX)\n"
                         + ") PRIMARY KEY (SingerId, AlbumId),\n"
                         + "  INTERLEAVE IN PARENT Singers ON DELETE CASCADE"));
-    Database db = op.waitFor().getResult();
-    System.out.println("Created database [" + db.getId() + "]");
+    op = op.waitFor(WaitForOption.timeout(2, TimeUnit.MINUTES));
+    Database db = op.getResult();
+    if (op.isSuccessful() && db.getState() == DatabaseInfo.State.READY) {
+      System.out.println("Created database [" + db.getId() + "]");
+    } else {
+      throw new RuntimeException(String.format(
+          "Error creating database: {successful: %b, state: %s}",
+          op.isSuccessful(), db.getState()));
+    }
   }
 
   // [START write]
@@ -198,10 +208,14 @@ static void read(DatabaseClient dbClient) {
 
   // [START add_marketing_budget]
   static void addMarketingBudget(DatabaseAdminClient adminClient, DatabaseId dbId) {
-    adminClient.updateDatabaseDdl(dbId.getInstanceId().getInstance(),
+    Operation op = adminClient.updateDatabaseDdl(
+        dbId.getInstanceId().getInstance(),
         dbId.getDatabase(),
         Arrays.asList("ALTER TABLE Albums ADD COLUMN MarketingBudget INT64"),
         null).waitFor();
+    if (!op.isSuccessful()) {
+      throw new RuntimeException("ALTER TABLE operation unsuccessful");
+    }
     System.out.println("Added MarketingBudget column");
   }
   // [END add_marketing_budget]