def METHOD_NAME(self) -> None:
    fatfs = wl_fatfsgen.WLFATFS()
    fatfs.plain_fatfs.create_file('TESTFILE')
    fatfs.init_wl()
    fatfs.wl_write_filesystem(CFG['output_file'])
    with open(CFG['output_file'], 'rb') as fs_file:
        file_system = fs_file.read()
    self.assertEqual(file_system[0x3000:0x300c], b'TESTFILE   \x20')  # check entry name and type
    self.assertEqual(file_system[0x2000:0x2006], b'\xf8\xff\xff\xff\x0f\x00')  # check fat