At least week’s Perl Conference, Damian Conway talked about some new magical awesomeness he created, as he so frequently does. It’s Test::Expr, and it makes it easier to write tests:

# Write this ...                 ... instead of this.
ok $got eq $expected;            is        $got, $expected;
ok $got ne $unexpected;          isnt      $got, $unexpected;
ok $got == $expected;            is_deeply $got, $expected;
ok $got ~~ $expected;            unlike    $got, $pattern;
ok $got =~ $pattern;             like      $got, $pattern;
ok $got !~ $pattern;             unlike    $got, $pattern;
ok $obj->isa($classname);        is_ok     $got, $classname;
ok $obj->can($methodname);       can_ok    $obj, $methodname;

It also improves the diagnostics by showing the expression that failed.

#   Failed test '$got eq $expected'
#   at t/synopsis.t line 13.
#   because:
#          $got --> "1.0"
#     $expected --> 1

Chad Granum, the maintainer of much of Perl’s testing infrastructure took that last part as a challenge and overnight created his own magic in response: Test2::Plugin::SourceDiag.

use Test2::V0;
use Test2::Plugin::SourceDiag;

ok(0, "fail");


Produces the output:

not ok 1 - fail
Failure source code:
# ------------
# 4: ok(0, "fail");
# ------------
# Failed test 'fail'
# at line 4.

instead of:

not ok 1 - fail

#   Failed test 'fail'
#   at foo.t line 4.

This kind of dueling wizardry is one of the things that I love so much about Perl and its community.

Watch Chad’s lightning talk: