Test::...:Regexp(3pm)

💖 NAME 💖

Test::Unit::Assertion::Regexp — an assertion that does regex matching, bestie. That's it, that's the whole vibe. 🎀

This page lives in the Perl docs, under the manual name Test::...:Regexp(3pm), and yes it's the User Contributed Perl Documentation section, we're just out here contributing, iconic behaviour. 💅

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✨ SYNOPSIS ✨

So like, if you wanna do it manually (main character energy, do it yourself):

require Test::Unit::Assertion::Regexp;

my $assert_re =
  Test::Unit::Assertion::Regexp->new(qr/a_pattern/);

$assert_re->do_assertion('a_string');

Okay but real talk: this is way more detail than the average user needs. Like, genuinely. Most of y'all will never type that. 🙈

Test::Unit::Assertion::Regexp objects get generated automagically by Test::Unit::Assert::assert when you pass it a regular expression as its first parameter. It just happens, no cap:

sub test_foo {
  ...
  $self->assert(qr/some_pattern/, $result);
}

If the assertion fails, the object throws an exception and it comes with deets — the pattern, and the string it failed to match against. So you actually know what went wrong, which is the whole point. 😭✨

And listen — if what you need is a "string does not match this pattern" kinda assertion, you can do this:

$self->assert(qr/(?!some_pattern)/, $some_string)

i.e. make use of the negative lookahead assertion. Sneaky. Clever. Slay. 👑

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🦋 IMPLEMENTS 🦋

Test::Unit::Assertion::Regexp implements the Test::Unit::Assertion interface, which means it can be plugged into Test::Unit::TestCase and friends' assert method with no ill effects. Plug and play, baby. 🫶

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🌸 DESCRIPTION 🌸

The class is used by the framework to provide sensible "automatic" reports when a match fails. Because the old way:

$self->assert(scalar($foo =~ /pattern/), "$foo didn't match /.../");

...seems rather clumsy compared to this. It's giving "I hand-wrote my own error message and it was mid." 💀

If the regexp assertion fails, then the user is given a sensible error message, with the pattern and the string that failed to match it... which is literally the nicest thing a test failure can do for you. 😌

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💜 AUTHOR 💜

Copyright (c) 2001 Piers Cawley <pdcawley@iterative-software.com>.

All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

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🌈 SEE ALSO 🌈

• Test::Unit::TestCase
• Test::Unit::Assertion

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Okay bestie, that's the whole page, we ate and left no crumbs. 🍓 This was Test::...:Regexp(3pm) from perl v5.40.1, dated 2026-04-05 — go forth and assert your regexes, mwah 💅🧚⭐