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.\" ========================================================================
.\"
.IX Title "Test2::Hub 3perl"
.TH Test2::Hub 3perl "2023-11-25" "perl v5.36.0" "Perl Programmers Reference Guide"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
Test2::Hub \- The conduit through which all events flow.
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\&    use Test2::Hub;
\&
\&    my $hub = Test2::Hub\->new();
\&    $hub\->send(...);
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
The hub is the place where all events get processed and handed off to the
formatter. The hub also tracks test state, and provides several hooks into the
event pipeline.
.SH "COMMON TASKS"
.IX Header "COMMON TASKS"
.SS "\s-1SENDING EVENTS\s0"
.IX Subsection "SENDING EVENTS"
.Vb 1
\&    $hub\->send($event)
.Ve
.PP
The \f(CW\*(C`send()\*(C'\fR method is used to issue an event to the hub. This method will
handle thread/fork sync, filters, listeners, \s-1TAP\s0 output, etc.
.SS "\s-1ALTERING OR REMOVING EVENTS\s0"
.IX Subsection "ALTERING OR REMOVING EVENTS"
You can use either \f(CW\*(C`filter()\*(C'\fR or \f(CW\*(C`pre_filter()\*(C'\fR, depending on your
needs. Both have identical syntax, so only \f(CW\*(C`filter()\*(C'\fR is shown here.
.PP
.Vb 2
\&    $hub\->filter(sub {
\&        my ($hub, $event) = @_;
\&
\&        my $action = get_action($event);
\&
\&        # No action should be taken
\&        return $event if $action eq \*(Aqnone\*(Aq;
\&
\&        # You want your filter to remove the event
\&        return undef if $action eq \*(Aqdelete\*(Aq;
\&
\&        if ($action eq \*(Aqdo_it\*(Aq) {
\&            my $new_event = copy_event($event);
\&            ... Change your copy of the event ...
\&            return $new_event;
\&        }
\&
\&        die "Should not happen";
\&    });
.Ve
.PP
By default, filters are not inherited by child hubs. That means if you start a
subtest, the subtest will not inherit the filter. You can change this behavior
with the \f(CW\*(C`inherit\*(C'\fR parameter:
.PP
.Vb 1
\&    $hub\->filter(sub { ... }, inherit => 1);
.Ve
.SS "\s-1LISTENING FOR EVENTS\s0"
.IX Subsection "LISTENING FOR EVENTS"
.Vb 2
\&    $hub\->listen(sub {
\&        my ($hub, $event, $number) = @_;
\&
\&        ... do whatever you want with the event ...
\&
\&        # return is ignored
\&    });
.Ve
.PP
By default listeners are not inherited by child hubs. That means if you start a
subtest, the subtest will not inherit the listener. You can change this behavior
with the \f(CW\*(C`inherit\*(C'\fR parameter:
.PP
.Vb 1
\&    $hub\->listen(sub { ... }, inherit => 1);
.Ve
.SS "POST-TEST \s-1BEHAVIORS\s0"
.IX Subsection "POST-TEST BEHAVIORS"
.Vb 2
\&    $hub\->follow_up(sub {
\&        my ($trace, $hub) = @_;
\&
\&        ... do whatever you need to ...
\&
\&        # Return is ignored
\&    });
.Ve
.PP
follow_up subs are called only once, either when done_testing is called, or in
an \s-1END\s0 block.
.SS "\s-1SETTING THE FORMATTER\s0"
.IX Subsection "SETTING THE FORMATTER"
By default an instance of Test2::Formatter::TAP is created and used.
.PP
.Vb 1
\&    my $old = $hub\->format(My::Formatter\->new);
.Ve
.PP
Setting the formatter will \s-1REPLACE\s0 any existing formatter. You may set the
formatter to undef to prevent output. The old formatter will be returned if one
was already set. Only one formatter is allowed at a time.
.SH "METHODS"
.IX Header "METHODS"
.ie n .IP "$hub\->send($event)" 4
.el .IP "\f(CW$hub\fR\->send($event)" 4
.IX Item "$hub->send($event)"
This is where all events enter the hub for processing.
.ie n .IP "$hub\->process($event)" 4
.el .IP "\f(CW$hub\fR\->process($event)" 4
.IX Item "$hub->process($event)"
This is called by send after it does any \s-1IPC\s0 handling. You can use this to
bypass the \s-1IPC\s0 process, but in general you should avoid using this.
.ie n .IP "$old = $hub\->format($formatter)" 4
.el .IP "\f(CW$old\fR = \f(CW$hub\fR\->format($formatter)" 4
.IX Item "$old = $hub->format($formatter)"
Replace the existing formatter instance with a new one. Formatters must be
objects that implement a \f(CW\*(C`$formatter\->write($event)\*(C'\fR method.
.ie n .IP "$sub = $hub\->listen(sub { ... }, %optional_params)" 4
.el .IP "\f(CW$sub\fR = \f(CW$hub\fR\->listen(sub { ... }, \f(CW%optional_params\fR)" 4
.IX Item "$sub = $hub->listen(sub { ... }, %optional_params)"
You can use this to record all events \s-1AFTER\s0 they have been sent to the
formatter. No changes made here will be meaningful, except possibly to other
listeners.
.Sp
.Vb 2
\&    $hub\->listen(sub {
\&        my ($hub, $event, $number) = @_;
\&
\&        ... do whatever you want with the event ...
\&
\&        # return is ignored
\&    });
.Ve
.Sp
Normally listeners are not inherited by child hubs such as subtests. You can
add the \f(CW\*(C`inherit => 1\*(C'\fR parameter to allow a listener to be inherited.
.ie n .IP "$hub\->unlisten($sub)" 4
.el .IP "\f(CW$hub\fR\->unlisten($sub)" 4
.IX Item "$hub->unlisten($sub)"
You can use this to remove a listen callback. You must pass in the coderef
returned by the \f(CW\*(C`listen()\*(C'\fR method.
.ie n .IP "$sub = $hub\->filter(sub { ... }, %optional_params)" 4
.el .IP "\f(CW$sub\fR = \f(CW$hub\fR\->filter(sub { ... }, \f(CW%optional_params\fR)" 4
.IX Item "$sub = $hub->filter(sub { ... }, %optional_params)"
.PD 0
.ie n .IP "$sub = $hub\->pre_filter(sub { ... }, %optional_params)" 4
.el .IP "\f(CW$sub\fR = \f(CW$hub\fR\->pre_filter(sub { ... }, \f(CW%optional_params\fR)" 4
.IX Item "$sub = $hub->pre_filter(sub { ... }, %optional_params)"
.PD
These can be used to add filters. Filters can modify, replace, or remove events
before anything else can see them.
.Sp
.Vb 3
\&    $hub\->filter(
\&        sub {
\&            my ($hub, $event) = @_;
\&
\&            return $event;    # No Changes
\&            return;           # Remove the event
\&
\&            # Or you can modify an event before returning it.
\&            $event\->modify;
\&            return $event;
\&        }
\&    );
.Ve
.Sp
If you are not using threads, forking, or \s-1IPC\s0 then the only difference between
a \f(CW\*(C`filter\*(C'\fR and a \f(CW\*(C`pre_filter\*(C'\fR is that \f(CW\*(C`pre_filter\*(C'\fR subs run first. When you
are using threads, forking, or \s-1IPC,\s0 pre_filters happen to events before they
are sent to their destination proc/thread, ordinary filters happen only in the
destination hub/thread.
.Sp
You cannot add a regular filter to a hub if the hub was created in another
process or thread. You can always add a pre_filter.
.ie n .IP "$hub\->unfilter($sub)" 4
.el .IP "\f(CW$hub\fR\->unfilter($sub)" 4
.IX Item "$hub->unfilter($sub)"
.PD 0
.ie n .IP "$hub\->pre_unfilter($sub)" 4
.el .IP "\f(CW$hub\fR\->pre_unfilter($sub)" 4
.IX Item "$hub->pre_unfilter($sub)"
.PD
These can be used to remove filters and pre_filters. The \f(CW$sub\fR argument is
the reference returned by \f(CW\*(C`filter()\*(C'\fR or \f(CW\*(C`pre_filter()\*(C'\fR.
.ie n .IP "$hub\->follow_op(sub { ... })" 4
.el .IP "\f(CW$hub\fR\->follow_op(sub { ... })" 4
.IX Item "$hub->follow_op(sub { ... })"
Use this to add behaviors that are called just before the hub is finalized. The
only argument to your codeblock will be a Test2::EventFacet::Trace instance.
.Sp
.Vb 2
\&    $hub\->follow_up(sub {
\&        my ($trace, $hub) = @_;
\&
\&        ... do whatever you need to ...
\&
\&        # Return is ignored
\&    });
.Ve
.Sp
follow_up subs are called only once, ether when done_testing is called, or in
an \s-1END\s0 block.
.ie n .IP "$sub = $hub\->add_context_acquire(sub { ... });" 4
.el .IP "\f(CW$sub\fR = \f(CW$hub\fR\->add_context_acquire(sub { ... });" 4
.IX Item "$sub = $hub->add_context_acquire(sub { ... });"
Add a callback that will be called every time someone tries to acquire a
context. It gets a single argument, a reference of the hash of parameters
being used the construct the context. This is your chance to change the
parameters by directly altering the hash.
.Sp
.Vb 4
\&    test2_add_callback_context_acquire(sub {
\&        my $params = shift;
\&        $params\->{level}++;
\&    });
.Ve
.Sp
This is a very scary \s-1API\s0 function. Please do not use this unless you need to.
This is here for Test::Builder and backwards compatibility. This has you
directly manipulate the hash instead of returning a new one for performance
reasons.
.Sp
\&\fBNote\fR Using this hook could have a huge performance impact.
.Sp
The coderef you provide is returned and can be used to remove the hook later.
.ie n .IP "$hub\->remove_context_acquire($sub);" 4
.el .IP "\f(CW$hub\fR\->remove_context_acquire($sub);" 4
.IX Item "$hub->remove_context_acquire($sub);"
This can be used to remove a context acquire hook.
.ie n .IP "$sub = $hub\->add_context_init(sub { ... });" 4
.el .IP "\f(CW$sub\fR = \f(CW$hub\fR\->add_context_init(sub { ... });" 4
.IX Item "$sub = $hub->add_context_init(sub { ... });"
This allows you to add callbacks that will trigger every time a new context is
created for the hub. The only argument to the sub will be the
Test2::API::Context instance that was created.
.Sp
\&\fBNote\fR Using this hook could have a huge performance impact.
.Sp
The coderef you provide is returned and can be used to remove the hook later.
.ie n .IP "$hub\->remove_context_init($sub);" 4
.el .IP "\f(CW$hub\fR\->remove_context_init($sub);" 4
.IX Item "$hub->remove_context_init($sub);"
This can be used to remove a context init hook.
.ie n .IP "$sub = $hub\->add_context_release(sub { ... });" 4
.el .IP "\f(CW$sub\fR = \f(CW$hub\fR\->add_context_release(sub { ... });" 4
.IX Item "$sub = $hub->add_context_release(sub { ... });"
This allows you to add callbacks that will trigger every time a context for
this hub is released. The only argument to the sub will be the
Test2::API::Context instance that was released. These will run in reverse
order.
.Sp
\&\fBNote\fR Using this hook could have a huge performance impact.
.Sp
The coderef you provide is returned and can be used to remove the hook later.
.ie n .IP "$hub\->remove_context_release($sub);" 4
.el .IP "\f(CW$hub\fR\->remove_context_release($sub);" 4
.IX Item "$hub->remove_context_release($sub);"
This can be used to remove a context release hook.
.ie n .IP "$hub\->\fBcull()\fR" 4
.el .IP "\f(CW$hub\fR\->\fBcull()\fR" 4
.IX Item "$hub->cull()"
Cull any \s-1IPC\s0 events (and process them).
.ie n .IP "$pid = $hub\->\fBpid()\fR" 4
.el .IP "\f(CW$pid\fR = \f(CW$hub\fR\->\fBpid()\fR" 4
.IX Item "$pid = $hub->pid()"
Get the process id under which the hub was created.
.ie n .IP "$tid = $hub\->\fBtid()\fR" 4
.el .IP "\f(CW$tid\fR = \f(CW$hub\fR\->\fBtid()\fR" 4
.IX Item "$tid = $hub->tid()"
Get the thread id under which the hub was created.
.ie n .IP "$hud = $hub\->\fBhid()\fR" 4
.el .IP "\f(CW$hud\fR = \f(CW$hub\fR\->\fBhid()\fR" 4
.IX Item "$hud = $hub->hid()"
Get the identifier string of the hub.
.ie n .IP "$uuid = $hub\->\fBuuid()\fR" 4
.el .IP "\f(CW$uuid\fR = \f(CW$hub\fR\->\fBuuid()\fR" 4
.IX Item "$uuid = $hub->uuid()"
If \s-1UUID\s0 tagging is enabled (see Test2::API) then the hub will have a \s-1UUID.\s0
.ie n .IP "$ipc = $hub\->\fBipc()\fR" 4
.el .IP "\f(CW$ipc\fR = \f(CW$hub\fR\->\fBipc()\fR" 4
.IX Item "$ipc = $hub->ipc()"
Get the \s-1IPC\s0 object used by the hub.
.ie n .IP "$hub\->set_no_ending($bool)" 4
.el .IP "\f(CW$hub\fR\->set_no_ending($bool)" 4
.IX Item "$hub->set_no_ending($bool)"
.PD 0
.ie n .IP "$bool = $hub\->no_ending" 4
.el .IP "\f(CW$bool\fR = \f(CW$hub\fR\->no_ending" 4
.IX Item "$bool = $hub->no_ending"
.PD
This can be used to disable auto-ending behavior for a hub. The auto-ending
behavior is triggered by an end block and is used to cull \s-1IPC\s0 events, and
output the final plan if the plan was '\s-1NO PLAN\s0'.
.ie n .IP "$bool = $hub\->active" 4
.el .IP "\f(CW$bool\fR = \f(CW$hub\fR\->active" 4
.IX Item "$bool = $hub->active"
.PD 0
.ie n .IP "$hub\->set_active($bool)" 4
.el .IP "\f(CW$hub\fR\->set_active($bool)" 4
.IX Item "$hub->set_active($bool)"
.PD
These are used to get/set the 'active' attribute. When true this attribute will
force \f(CW\*(C`hub\->finalize()\*(C'\fR to take action even if there is no plan, and no
tests have been run. This flag is useful for plugins that add follow-up
behaviors that need to run even if no events are seen.
.SS "\s-1STATE METHODS\s0"
.IX Subsection "STATE METHODS"
.ie n .IP "$hub\->\fBreset_state()\fR" 4
.el .IP "\f(CW$hub\fR\->\fBreset_state()\fR" 4
.IX Item "$hub->reset_state()"
Reset all state to the start. This sets the test count to 0, clears the plan,
removes the failures, etc.
.ie n .IP "$num = $hub\->count" 4
.el .IP "\f(CW$num\fR = \f(CW$hub\fR\->count" 4
.IX Item "$num = $hub->count"
Get the number of tests that have been run.
.ie n .IP "$num = $hub\->failed" 4
.el .IP "\f(CW$num\fR = \f(CW$hub\fR\->failed" 4
.IX Item "$num = $hub->failed"
Get the number of failures (Not all failures come from a test fail, so this
number can be larger than the count).
.ie n .IP "$bool = $hub\->ended" 4
.el .IP "\f(CW$bool\fR = \f(CW$hub\fR\->ended" 4
.IX Item "$bool = $hub->ended"
True if the testing has ended. This \s-1MAY\s0 return the stack frame of the tool that
ended the test, but that is not guaranteed.
.ie n .IP "$bool = $hub\->is_passing" 4
.el .IP "\f(CW$bool\fR = \f(CW$hub\fR\->is_passing" 4
.IX Item "$bool = $hub->is_passing"
.PD 0
.ie n .IP "$hub\->is_passing($bool)" 4
.el .IP "\f(CW$hub\fR\->is_passing($bool)" 4
.IX Item "$hub->is_passing($bool)"
.PD
Check if the overall test run is a failure. Can also be used to set the
pass/fail status.
.ie n .IP "$hub\->plan($plan)" 4
.el .IP "\f(CW$hub\fR\->plan($plan)" 4
.IX Item "$hub->plan($plan)"
.PD 0
.ie n .IP "$plan = $hub\->plan" 4
.el .IP "\f(CW$plan\fR = \f(CW$hub\fR\->plan" 4
.IX Item "$plan = $hub->plan"
.PD
Get or set the plan. The plan must be an integer larger than 0, the string
\&'\s-1NO PLAN\s0', or the string '\s-1SKIP\s0'.
.ie n .IP "$bool = $hub\->check_plan" 4
.el .IP "\f(CW$bool\fR = \f(CW$hub\fR\->check_plan" 4
.IX Item "$bool = $hub->check_plan"
Check if the plan and counts match, but only if the tests have ended. If tests
have not ended this will return undef, otherwise it will be a true/false.
.SH "THIRD PARTY META-DATA"
.IX Header "THIRD PARTY META-DATA"
This object consumes Test2::Util::ExternalMeta which provides a consistent
way for you to attach meta-data to instances of this class. This is useful for
tools, plugins, and other extensions.
.SH "SOURCE"
.IX Header "SOURCE"
The source code repository for Test2 can be found at
\&\fIhttp://github.com/Test\-More/test\-more/\fR.
.SH "MAINTAINERS"
.IX Header "MAINTAINERS"
.IP "Chad Granum <exodist@cpan.org>" 4
.IX Item "Chad Granum <exodist@cpan.org>"
.SH "AUTHORS"
.IX Header "AUTHORS"
.PD 0
.IP "Chad Granum <exodist@cpan.org>" 4
.IX Item "Chad Granum <exodist@cpan.org>"
.PD
.SH "COPYRIGHT"
.IX Header "COPYRIGHT"
Copyright 2020 Chad Granum <exodist@cpan.org>.
.PP
This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.
.PP
See \fIhttp://dev.perl.org/licenses/\fR