Gregor Goldbach
and 1 contributors


Test::BOM - Test strings and files for BOM


version 0.001


    use Test::More;
    use Test::BOM




This module helps you with testing for byte-order-marks in strings and files.

If you came across this module while looking for other ways to deal with byte-order-marks you might find what you need in the "SEE ALSO" section below.

If you don't know anything about automated testing in Perl then you should read about Test::More before preceding. This module uses the Test::Builder framework.

Byte-order-marks are by definition to be found at the beginning of any content, so the functions this module provides take a look at the start of either a string or a file. It does this by using functions from String::BOM and basically just wraps them for use with Test::Builder.

By default the following functions are imported into your namespace: string_has_bom, string_hasnt_bom, file_has_bom, file_hasnt_bom.


string_has_bom ($string)

Passes if the string has a BOM, fails if not.

string_hasnt_bom ($string)

Passes if string doesn't have a BOM, fails if it has.

file_has_bom ($filename)

Passes if the file has a BOM, fails if it doesn't.

file_hasnt_bom ($filename)

Passes if the file doesn't have a BOM, fails if it has.


There are some distributions that help you dealing with BOMs in different ways:

String::BOM is used by this module to check for BOM.
File::BOM::Utils contains functions to check for, add and remove BOM from files.
File::BOM can be used to actually read from files that have BOMs as seamlessly as possible.
PPI::Token::BOM represents a BOM when using PPI to parse perl.
The distribution Dist::Zilla::Plugin::Web contains the module Dist::Zilla::Plugin::Web::StripBOM that strips BOM from files.

Additional information about BOM and it's usage: is the FAQ for the BOM from the Unicode Consortium. explains how Microsoft wants the BOM to be used. Since this document dates from 2018 (as of this writing) it's very likely to get in contact with files containing BOM.


Gregor Goldbach <>


This software is copyright (c) 2018 by Gregor Goldbach.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.