Test2::Util::Grabber(3perl) Perl Programmers Reference Guide Test2::Util::Grabber(3perl)

Test2::Util::Grabber - Object used to temporarily intercept all events.

Once created this object will intercept and stash all events sent to the shared Test2::Hub object. Once the object is destroyed, events will once again be sent to the shared hub.

use Test2 qw/Core Grab/;
my $grab = grab();
# Generate some events, they are intercepted.
ok(1, "pass");
ok(0, "fail");
my $events_a = $grab->flush;
# Generate some more events, they are intercepted.
ok(1, "pass");
ok(0, "fail");
# Same as flush, except it destroys the grab object.
my $events_b = $grab->finish;

After calling finish() the grab object is destroyed and $grab is set to undef. $events_a is an arrayref with the first two events. $events_b is an arrayref with the second two events.

$grab = grab()
This lets you intercept all events for a section of code without adding anything to your call stack. This is useful for things that are sensitive to changes in the stack depth. 
my $grab = grab();
    ok(1, 'foo');
    ok(0, 'bar');
# $grab is magically undef after this.
my $events = $grab->finish;
is(@$events, 2, "grabbed two events.");

When you call finish() the $grab object will automagically undef itself, but only for the reference used in the method call. If you have other references to the $grab object they will not be set to undef.

If the $grab object is destroyed without calling finish(), it will automatically clean up after itself and restore the parent hub.

{
    my $grab = grab();
    # Things are grabbed
}
# Things are back to normal

By default the hub used has "no_ending" set to true. This will prevent the hub from enforcing that you issued a plan and ran at least one test. You can turn enforcement back one like this:

$grab->hub->set_no_ending(0);

With "no_ending" turned off, "finish" will run the post-test checks to enforce the plan and that tests were run. In many cases this will result in additional events in your events array.

$grab = $class->new()
Create a new grab object, immediately starts intercepting events.
$ar = $grab->flush()
Get an arrayref of all the events so far, clearing the grab objects internal list.
$ar = $grab->events()
Get an arrayref of all events so far. Does not clear the internal list.
$ar = $grab->finish()
Get an arrayref of all the events, then destroy the grab object.
$hub = $grab->hub()
Get the hub that is used by the grab event.

By default the hub used has "no_ending" set to true. This will prevent the hub from enforcing that you issued a plan and ran at least one test. You can turn enforcement back one like this:

$grab->hub->set_no_ending(0);

With "no_ending" turned off, "finish" will run the post-test checks to enforce the plan and that tests were run. In many cases this will result in additional events in your events array.

Test2::Tools::Intercept - Accomplish the same thing, but using blocks instead.

The source code repository for Test2 can be found at https://github.com/Test-More/Test2-Suite/.

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/

2024-09-01 perl v5.40.0