cache_fetch_test.dart

  test('Fetch Pdf And Cache', () async {
    final response = await manager.downloadFileSimple('http://www.africau.edu/images/default/sample.pdf', null);
    final directory = await getApplicationDocumentsDirectory();
    await Directory('${directory.path}').create();
    await Directory('${directory.path}/vb2').create();
    final path = '${directory.path}/vb2/1.pdf';
    final file = File(path);
    final fileWithData = await file.writeAsBytes(response.data!);
    expect(await fileWithData.exists(), true);
  });