Test2::Compare - Test2 extension for writing deep comparison tools.
This library is the driving force behind deep comparison tools such as
Test2::Tools::Compare::is() and
Test2::Tools::ClassicCompare::is_deeply().
package Test2::Tools::MyCheck;
use Test2::Compare::MyCheck;
use Test2::Compare qw/compare/;
sub MyCheck {
my ($got, $exp, $name, @diag) = @_;
my $ctx = context();
my $delta = compare($got, $exp, \&convert);
if ($delta) {
$ctx->fail($name, $delta->diag, @diag);
}
else {
$ctx->ok(1, $name);
}
$ctx->release;
return !$delta;
}
sub convert {
my $thing = shift;
return $thing if blessed($thing) && $thing->isa('Test2::Compare::MyCheck');
return Test2::Compare::MyCheck->new(stuff => $thing);
}
See the Test2::Compare::Base manpage for details about writing a custom check.
- $delta = compare($got, $expect, \&convert)
-
This will compare the structures in
$got with those in $expect, The
convert sub should convert vanilla structures inside $expect into checks.
If there are differences in the structures they will be reported back as an
the Test2::Compare::Delta manpage tree.
- $build = get_build()
-
Get the current global build, if any.
- push_build($build)
-
Set the current global build.
- $build = pop_build($build)
-
Unset the current global build. This will throw an exception if the build
passed in is different from the current global.
- build($class, sub { ... })
-
Run the provided codeblock with a new instance of
$class as the current
build. Returns the new build.
- $check = convert($thing)
-
- $check = convert($thing, $config)$check = convert($thing, $config)
-
This convert function is used by
strict_convert() and relaxed_convert()
under the hood. It can also be used as the basis for other convert functions.
If you want to use it with a custom configuration you should wrap it in another
sub like so:
sub my_convert {
my $thing_to_convert = shift;
return convert(
$thing_to_convert,
{ ... }
);
}
Or the short variant:
sub my_convert { convert($_[0], { ... }) }
There are several configuration options, here they are with the default setting
listed first:
- implicit_end => 1
-
This option toggles array/hash boundaries. If this is true then no extra hash
keys or array indexes will be allowed. This setting effects generated compare
objects as well as any passed in.
- use_regex => 1
-
This option toggles regex matching. When true (default) regexes are converted
to checks such that values must match the regex. When false regexes will be
compared to see if they are identical regexes.
- use_code => 0
-
This option toggles code matching. When false (default) coderefs in structures
must be the same coderef as specified. When true coderefs will be run to verify
the value being checked.
- $check = strict_convert($thing)
-
Convert
$thing to an the Test2::Compare::* manpage object. This will behave strictly
which means it uses these settings:
- implicit_end => 1implicit_end => 1
-
Array bounds will be checked when this object is used in a comparison. No
unexpected hash keys can be present.
- use_code => 0use_code => 0
-
Sub references will be compared as refs (IE are these sub refs the same ref?)
- use_regex => 0
-
Regexes will be compared directly (IE are the regexes the same?)
- $compare = relaxed_convert($thing)
-
Convert
$thing to an the Test2::Compare::* manpage object. This will be relaxed which
means it uses these settings:
- implicit_end => 0
-
Array bounds will not be checked when this object is used in a comparison.
Unexpected hash keys can be present.
- use_code => 1
-
Sub references will be run to verify a value.
- use_regex => 1use_regex => 1
-
Values will be checked against any regexes provided.
use Test2::Compare qw/compare convert/;
sub my_like($$;$@) {
my ($got, $exp, $name, @diag) = @_;
my $ctx = context();
# A custom converter that does the same thing as the one used by like()
my $convert = sub {
my $thing = shift;
return convert(
$thing,
{
implicit_end => 0,
use_code => 1,
use_regex => 1,
}
);
};
my $delta = compare($got, $exp, $convert);
if ($delta) {
$ctx->fail($name, $delta->diag, @diag);
}
else {
$ctx->ok(1, $name);
}
$ctx->release;
return !$delta;
}
The work of a comparison tool is done by 3 entities:
compare()compare()
-
The
compare() function takes the structure you got, the specification you
want to check against, and a \&convert sub that will convert anything that
is not an instance of an the Test2::Compare::Base manpage subclass into one.
This tool will use the \&convert function on the specification, and then
produce an the Test2::Compare::Delta manpage structure that outlines all the ways the
structure you got deviates from the specification.
- \&convert
-
Converts anything that is not an instance of an the Test2::Compare::Base manpage
subclass, and turns it into one. The objects this produces are able to check
that a structure matches a specification.
- $delta
-
An instance of the Test2::Compare::Delta manpage is ultimately returned. This object
represents all the ways in with the structure you got deviated from the
specification. The delta is a tree and may contain child deltas for nested
structures.
The delta is capable of rendering itself as a table, use @lines =
$delta->diag to get the table (lines in @lines will not be terminated
with "\n").
The convert() function provided by this package contains all the
specification behavior of like() and is(). It is intended to be wrapped
in a sub that passes in a configuration hash, which allows you to control the
behavior.
You are free to write your own $check = compare($thing) function, it just
needs to accept a single argument, and produce a single instance of an
the Test2::Compare::Base manpage subclass.
The source code repository for Test2-Suite can be found at
https://github.com/Test-More/Test2-Suite/.
- Chad Granum
-
- Chad Granum <exodist@cpan.org>Chad Granum
-
Copyright 2018 Chad Granum <exodist@cpan.org>.
This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.
See http://dev.perl.org/licenses/
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