bpo-43265: Improve sqlite3.Connection.backup error handling (GH-24586)

diff --git a/Lib/sqlite3/test/backup.py b/Lib/sqlite3/test/backup.py
index cbe24df..4e30594 100644
--- a/Lib/sqlite3/test/backup.py
+++ b/Lib/sqlite3/test/backup.py
@@ -149,10 +149,7 @@ def test_database_source_name(self):
         with self.assertRaises(sqlite.OperationalError) as cm:
             with sqlite.connect(':memory:') as bck:
                 self.cx.backup(bck, name='non-existing')
-        self.assertIn(
-            str(cm.exception),
-            ['SQL logic error', 'SQL logic error or missing database']
-        )
+        self.assertIn("unknown database", str(cm.exception))
 
         self.cx.execute("ATTACH DATABASE ':memory:' AS attached_db")
         self.cx.execute('CREATE TABLE attached_db.foo (key INTEGER)')