private static byte[] string2Bytes(String s) {
    try {
      return s.getBytes("UTF-8");
    } catch (UnsupportedEncodingException e) {
      throw new RuntimeException("UTF-8 encoding is unsupported");
    }
  }
Base32String implementation is not the same as that of RFC 4648, it drops
the last incomplete chunk and thus accepts encoded strings that should have
been rejected; also this results in multiple encoded strings being decoded
to the same byte array.
This test will catch any changes made regarding this behavior.
javatests/com/google/android/apps/authenticator/util/Base32StringTest.java