Test::Bits - Provides a bits_is() subroutine for testing binary data


version 0.02


  use Test::Bits;

      [ 0b0010101, 0b01111100 ],
      'binary data contains expected values'


This module provides a single subroutine, bits_is(), for testing binary data.

This module is quite similar to Test::BinaryData and Test::HexString in concept. The difference is that this module shows failure diagnostics in a different way, and has a slightly different calling style. Depending on the nature of the data you're working with, this module may be easier to work with.

In particular, when you're doing a lot of bit twiddling, this module's diagnostic output may make it easier to diagnose failures. A typical failure diagnostic will look like this:

   The two pieces of binary data are not the same length (got 2, expected 3).
   Binary data begins differing at byte 1.
     Got:    01111000
     Expect: 01111001

Note that the bytes are numbered starting from 0 in the diagnostic output.


The bits_is() subroutine takes two required arguments and an optional test name.

The first argument should be a plain scalar containing binary data. If it contains any UTF-8 characters an error will be thrown.

The second argument should be an array reference of numbers from 0-255 representing the expected value of each byte in the first argument.

This allows you write the numbers out in binary format (0bXXXXXXXX) for test cases if you wish to.


Please report any bugs or feature requests to, or through the web interface at I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.


Dave Rolsky <>


This software is Copyright (c) 2013 by MaxMind, Inc..

This is free software, licensed under:

  The Artistic License 2.0 (GPL Compatible)