Verify path.join is called with certain parameters in mocktail

I have a function similar to this one below:

Future<void> saveFile ({
  required String fileName,
  required Uint8List bytes,
  bool permanent = true,
) async {
  final directory = permanent ? 'permanentFolder' : 'tempFolder';
  final filePath = join(directory, fileName);
  final file = File(filePath);
  await file.create(recursive: true);
  await file.writeAsBytes(bytes);
}

I want to write a test on it that verifies that the method join from package:path/path.dart is being called with the right parameters.

await saveFile(fileName: 'name', bytes: []);
verify(() => join('permanentFolder', 'name')).called(1);
await saveFile(fileName: 'name', bytes: [], permanent: false);
verify(() => join('tempFolder', 'name')).called(1);

I have not been successful in mocking the join function in order for this test to pass.