samples: parameterises create backup version time

samples/samples/backup_sample.py

@@ -26,18 +26,12 @@
 
 
 # [START spanner_create_backup]
-def create_backup(instance_id, database_id, backup_id):
+def create_backup(instance_id, database_id, backup_id, version_time):
     """Creates a backup for a database."""
     spanner_client = spanner.Client()
     instance = spanner_client.instance(instance_id)
     database = instance.database(database_id)
 
-    # Sets the version time as the current server time
-    version_time = None
-    with database.snapshot() as snapshot:
-        results = snapshot.execute_sql("SELECT CURRENT_TIMESTAMP()")
-        version_time = list(results)[0][0]
-
     # Create a backup
     expire_time = datetime.utcnow() + timedelta(days=14)
     backup = instance.backup(backup_id, database=database, expire_time=expire_time, version_time=version_time)

samples/samples/backup_sample_test.py

@@ -67,7 +67,12 @@ def database(spanner_instance):
 
 
 def test_create_backup(capsys, database):
-    backup_sample.create_backup(INSTANCE_ID, DATABASE_ID, BACKUP_ID)
+    version_time = None
+    with database.snapshot() as snapshot:
+        results = snapshot.execute_sql("SELECT CURRENT_TIMESTAMP()")
+        version_time = list(results)[0][0]
+
+    backup_sample.create_backup(INSTANCE_ID, DATABASE_ID, BACKUP_ID, version_time)
     out, _ = capsys.readouterr()
     assert BACKUP_ID in out