Test2::Manual::Anatomy::Context(3) User Contributed Perl Documentation
NAME
Test2::Manual::Anatomy::Context - Internals documentation for the
Context objects.
DESCRIPTION
This document explains how the Test2::API::Context object works.
WHAT IS THE CONTEXT OBJECT?
The context object is one of the key components of Test2, and makes
many features possible that would otherwise be impossible. Every test
tool starts by getting a context, and ends by releasing the context. A
test tool does all its work between getting and releasing the context.
The context instance is the primary interface for sending events to the
Test2 stack. Finally the context system is responsible for tracking
what file and line number a tool operates on, which is critical for
debugging.
PRIMARY INTERFACE FOR TEST TOOLS
Nearly every Test2 based tool should start by calling $ctx =
Test2::API::context() in order to get a context object, and should end
by calling "$ctx->release()". Once a tool has its context object it can
call methods on the object to send events or have other effects. Nearly
everything a test tool needs to do should be done through the context
object.
TRACK FILE AND LINE NUMBERS FOR ERROR REPORTING
When you call "Test2::API::Context" a new context object will be
returned. If there is already a context object in effect (from a
different point in the stack) you will get a clone of the existing one.
If there is not already a current context then a completely new one
will be generated. When a new context is generated Test2 will determine
the file name and line number for your test code, these will be used
when reporting any failures.
Typically the file and line number will be determined using caller() to
look at your tools caller. The $Test::Builder::Level will be respected
if detected, but is discouraged in favor of just using context objects
at every level.
When calling Test2::API::Context() you can specify the "level =>
$count" arguments if you need to look at a deeper caller.
PRESERVE $?, $!, $^E AND $@
When you call Test2::API::context() the current values of $?, $!, $^E,
and $@ are stored in the context object itself. Whenever the context is
released the original values of these variables will be restored. This
protects the variables from any side effects caused by testing tools.
FINALIZE THE API STATE
Test2::API works via a hidden singleton instance of
Test2::API::Instance. The singleton has some state that is not set in
stone until the last possible minute. The last possible minute happens
to be the first time a context is acquired. State includes IPC
instance, Formatter class, Root PID, etc.
FIND/CREATE THE CURRENT/ROOT HUB
Test2 has a stack of hubs, the stack can be accessed via
Test2::API::test2_stack. When you get a context it will find the
current hub, if there is no current hub then the root one will be
initialized.
PROVIDE HOOKS
There are hooks that run when contexts are created, found, and
released. See Test2::API for details on these hooks and how to use
them.
SEE ALSO
Test2::Manual(3) - Primary index of the manual.
SOURCE
The source code repository for Test2-Manual can be found at
https://github.com/Test-More/test-more/.
MAINTAINERS
Chad Granum <exodist@cpan.org>
AUTHORS
Chad Granum <exodist@cpan.org>
COPYRIGHT
Copyright 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/
perl v5.34.3 2025-05-03
Test2::Manual::Anatomy::Context(3)
test-simple 1.302.211 - Generated Sat May 10 07:00:57 CDT 2025