test: deflake autocommit sample test (#255)

* test: deflake autocommit sample test

* test: fix DDL call

Co-authored-by: larkee <larkee@users.noreply.github.com>

samples/samples/autocommit_test.py

@@ -8,8 +8,6 @@
 
 from google.api_core.exceptions import Aborted
 from google.cloud import spanner
-from google.cloud.spanner_dbapi import connect
-import mock
 import pytest
 from test_utils.retry import RetryErrors
 
@@ -53,13 +51,13 @@ def database(spanner_instance):
 
 @RetryErrors(exception=Aborted, max_tries=2)
 def test_enable_autocommit_mode(capsys, database):
-    connection = connect(INSTANCE_ID, DATABASE_ID)
-    cursor = connection.cursor()
-
-    with mock.patch(
-        "google.cloud.spanner_dbapi.connection.Cursor", return_value=cursor,
-    ):
-        autocommit.enable_autocommit_mode(INSTANCE_ID, DATABASE_ID)
-        out, _ = capsys.readouterr()
-        assert "Autocommit mode is enabled." in out
-        assert "SingerId: 13, AlbumId: Russell, AlbumTitle: Morales" in out
+    # Delete table if it exists for retry attempts.
+    table = database.table('Singers')
+    if table.exists():
+        op = database.update_ddl(["DROP TABLE Singers"])
+        op.result()
+
+    autocommit.enable_autocommit_mode(INSTANCE_ID, DATABASE_ID)
+    out, _ = capsys.readouterr()
+    assert "Autocommit mode is enabled." in out
+    assert "SingerId: 13, AlbumId: Russell, AlbumTitle: Morales" in out