add error test case

Author: wty-Bryant

feature/s3/transfermanager/testdata/file-contains-non-default-delimiter/fo@o

@@ -219,6 +219,12 @@ func TestUploadDirectory(t *testing.T) {
 			},
 			expectErr: "banned key",
 		},
+		"error when a file contains customized delimiter": {
+			source:      filepath.Join(root, "file-contains-non-default-delimiter"),
+			recursive:   true,
+			s3Delimiter: "@",
+			expectErr:   "contains delimiter @",
+		},
 		"error when a symlink refers to its upper dir": {
 			source:         filepath.Join(root, "multi-file-contain-symlink"),
 			followSymLinks: true,