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Test2::Event(3) |
User Contributed Perl Documentation |
Test2::Event(3) |
Test2::Event - Base class for events
Base class for all event objects that get passed through Test2.
package Test2::Event::MyEvent;
use strict;
use warnings;
# This will make our class an event subclass (required)
use base 'Test2::Event';
# Add some accessors (optional)
# You are not obligated to use HashBase, you can use any object tool you
# want, or roll your own accessors.
use Test2::Util::HashBase qw/foo bar baz/;
# Use this if you want the legacy API to be written for you, for this to
# work you will need to implement a facet_data() method.
use Test2::Util::Facets2Legacy;
# Chance to initialize some defaults
sub init {
my $self = shift;
# no other args in @_
$self->set_foo('xxx') unless defined $self->foo;
...
}
# This is the new way for events to convey data to the Test2 system
sub facet_data {
my $self = shift;
# Get common facets such as 'about', 'trace' 'amnesty', and 'meta'
my $facet_data = $self->common_facet_data();
# Are you making an assertion?
$facet_data->{assert} = {pass => 1, details => 'my assertion'};
...
return $facet_data;
}
1;
- $trace = $e->trace
- Get a snapshot of the Test2::EventFacet::Trace as it was when this event
was generated
- $bool_or_undef = $e->related($e2)
- Check if 2 events are related. In this case related means their traces
share a signature meaning they were created with the same context (or at
the very least by contexts which share an id, which is the same thing
unless someone is doing something very bad).
This can be used to reliably link multiple events created by
the same tool. For instance a failing test like
"ok(0, "fail"" will generate
2 events, one being a Test2::Event::Ok, the other being a
Test2::Event::Diag, both of these events are related having been created
under the same context and by the same initial tool (though multiple
tools may have been nested under the initial one).
This will return "undef" if
the relationship cannot be checked, which happens if either event has an
incomplete or missing trace. This will return 0
if the traces are complete, but do not match. 1
will be returned if there is a match.
- $e->add_amnesty({tag => $TAG, details => $DETAILS});
- This can be used to add amnesty to this event. Amnesty only effects
failing assertions in most cases, but some formatters may display them for
passing assertions, or even non-assertions as well.
Amnesty will prevent a failed assertion from causing the
overall test to fail. In other words it marks a failure as expected and
allowed.
Note: This is how 'TODO' is implemented under the hood.
TODO is essentially amnesty with the 'TODO' tag. The details are the
reason for the TODO.
- $uuid = $e->uuid
- If UUID tagging is enabled (See Test::API) then any event that has made
its way through a hub will be tagged with a UUID. A newly created event
will not yet be tagged in most cases.
- $class = $e->load_facet($name)
- This method is used to load a facet by name (or key). It will attempt to
load the facet class, if it succeeds it will return the class it loaded.
If it fails it will return "undef". This
caches the result at the class level so that future calls will be faster.
The $name variable should be the key
used to access the facet in a facets hashref. For instance the assertion
facet has the key 'assert', the information facet has the 'info' key,
and the error facet has the key 'errors'. You may include or omit the
's' at the end of the name, the method is smart enough to try both the
's' and no-'s' forms, it will check what you provided first, and if that
is not found it will add or strip the 's and try again.
- @classes = $e->FACET_TYPES()
- @classes = Test2::Event->FACET_TYPES()
- This returns a list of all facets that have been loaded using the
"load_facet()" method. This will not
return any classes that have not been loaded, or have been loaded directly
without a call to "load_facet()".
Note: The core facet types are automatically loaded and
populated in this list.
- $hashref = $e->common_facet_data();
- This can be used by subclasses to generate a starting facet data hashref.
This will populate the hashref with the trace, meta, amnesty, and about
facets. These facets are nearly always produced the same way for all
events.
- $hashref = $e->facet_data()
- If you do not override this then the default implementation will attempt
to generate facets from the legacy API. This generation is limited only to
what the legacy API can provide. It is recommended that you override this
method and write out explicit facet data.
- $hashref = $e->facets()
- This takes the hashref from
"facet_data()" and blesses each facet
into the proper "Test2::EventFacet::*"
subclass. If no class can be found for any given facet it will be passed
along unchanged.
- @errors = $e->validate_facet_data();
- @errors = $e->validate_facet_data(%params);
- @errors = $e->validate_facet_data(\%facets, %params);
- @errors = Test2::Event->validate_facet_data(%params);
- @errors = Test2::Event->validate_facet_data(\%facets, %params);
- This method will validate facet data and return a list of errors. If no
errors are found this will return an empty list.
This can be called as an object method with no arguments, in
which case the "facet_data()" method
will be called to get the facet data to be validated.
When used as an object method the
"\%facet_data" argument may be
omitted.
When used as a class method the
"\%facet_data" argument is
required.
Remaining arguments will be slurped into a
%params hash.
Currently only 1 parameter is defined:
- require_facet_class => $BOOL
- When set to true (default is false) this will reject any facets where a
facet class cannot be found. Normally facets without classes are assumed
to be custom and are ignored.
WHAT ARE FACETS?
Facets are how events convey their purpose to the Test2 internals
and formatters. An event without facets will have no intentional effect on
the overall test state, and will not be displayed at all by most formatters,
except perhaps to say that an event of an unknown type was seen.
Facets are produced by the
"facet_data()" subroutine, which you
should nearly-always override.
"facet_data()" is expected to return a
hashref where each key is the facet type, and the value is either a hashref
with the data for that facet, or an array of hashrefs. Some facets must be
defined as single hashrefs, some must be defined as an array of hashrefs, No
facets allow both.
"facet_data()" MUST NOT
bless the data it returns, the main hashref, and nested facet hashrefs
MUST be bare, though items contained within each facet may be
blessed. The data returned by this method should also be copies of
the internal data in order to prevent accidental state modification.
"facets()" takes the data from
"facet_data()" and blesses it into the
"Test2::EventFacet::*" packages. This is
rarely used however, the EventFacet packages are primarily for convenience
and documentation. The EventFacet classes are not used at all internally,
instead the raw data is used.
Here is a list of facet types by package. The packages are not
used internally, but are where the documentation for each type is kept.
Note: Every single facet type has the
'details' field. This field is always intended for
human consumption, and when provided, should explain the 'why' for the
facet. All other fields are facet specific.
- about => {...}
- Test2::EventFacet::About
This contains information about the event itself such as the
event package name. The "details"
field for this facet is an overall summary of the event.
- assert => {...}
- Test2::EventFacet::Assert
This facet is used if an assertion was made. The
"details" field of this facet is the
description of the assertion.
- control => {...}
- Test2::EventFacet::Control
This facet is used to tell the Test2::Event::Hub about special
actions the event causes. Things like halting all testing, terminating
the current test, etc. In this facet the
"details" field explains why any
special action was taken.
Note: This is how bail-out is implemented.
- meta => {...}
- Test2::EventFacet::Meta
The meta facet contains all the meta-data attached to the
event. In this case the "details"
field has no special meaning, but may be present if something sets the
'details' meta-key on the event.
- parent => {...}
- Test2::EventFacet::Parent
This facet contains nested events and similar details for
subtests. In this facet the "details"
field will typically be the name of the subtest.
- plan => {...}
- Test2::EventFacet::Plan
This facet tells the system that a plan has been set. The
"details" field of this is usually
left empty, but when present explains why the plan is what it is, this
is most useful if the plan is to skip-all.
- trace => {...}
- Test2::EventFacet::Trace
This facet contains information related to when and where the
event was generated. This is how the test file and line number of a
failure is known. This facet can also help you to tell if tests are
related.
In this facet the "details"
field overrides the "failed at test_file.t line 42." message
provided on assertion failure.
- amnesty => [{...}, ...]
- Test2::EventFacet::Amnesty
The amnesty facet is a list instead of a single item, this is
important as amnesty can come from multiple places at once.
For each instance of amnesty the
"details" field explains why amnesty
was granted.
Note: Outside of formatters amnesty only acts to
forgive a failing assertion.
- errors => [{...}, ...]
- Test2::EventFacet::Error
The errors facet is a list instead of a single item, any
number of errors can be listed. In this facet
"details" describes the error, or may
contain the raw error message itself (such as an exception). In perl
exception may be blessed objects, as such the raw data for this facet
may contain nested items which are blessed.
Not all errors are considered fatal, there is a
"fail" field that must be set for an
error to cause the test to fail.
Note: This facet is unique in that the field name is
'errors' while the package is 'Error'. This is because this is the only
facet type that is both a list, and has a name where the plural is not
the same as the singular. This may cause some confusion, but I feel it
will be less confusing than the alternative.
- info => [{...}, ...]
- Test2::EventFacet::Info
The 'info' facet is a list instead of a single item, any
quantity of extra information can be attached to an event. Some
information may be critical diagnostics, others may be simply commentary
in nature, this is determined by the
"debug" flag.
For this facet the "details"
flag is the info itself. This info may be a string, or it may be a data
structure to display. This is one of the few facet types that may
contain blessed items.
- $bool = $e->causes_fail
- Returns true if this event should result in a test failure. In general
this should be false.
- $bool = $e->increments_count
- Should be true if this event should result in a test count increment.
- $e->callback($hub)
- If your event needs to have extra effects on the Test2::Hub you can
override this method.
This is called BEFORE your event is passed to the
formatter.
- $num = $e->nested
- If this event is nested inside of other events, this should be the depth
of nesting. (This is mainly for subtests)
- $bool = $e->global
- Set this to true if your event is global, that is ALL threads and
processes should see it no matter when or where it is generated. This is
not a common thing to want, it is used by bail-out and skip_all to end
testing.
- $code = $e->terminate
- This is called AFTER your event has been passed to the formatter.
This should normally return undef, only change this if your event should
cause the test to exit immediately.
If you want this event to cause the test to exit you should
return the exit code here. Exit code of 0 means exit success, any other
integer means exit with failure.
This is used by Test2::Event::Plan to exit 0 when the plan is
'skip_all'. This is also used by Test2::Event:Bail to force the test to
exit with a failure.
This is called after the event has been sent to the formatter
in order to ensure the event is seen and understood.
- $msg = $e->summary
- This is intended to be a human readable summary of the event. This should
ideally only be one line long, but you can use multiple lines if
necessary. This is intended for human consumption. You do not need to make
it easy for machines to understand.
The default is to simply return the event package name.
- ($count, $directive, $reason) = $e->sets_plan()
- Check if this event sets the testing plan. It will return an empty list if
it does not. If it does set the plan it will return a list of 1 to 3 items
in order: Expected Test Count, Test Directive, Reason for directive.
- $bool = $e->diagnostics
- True if the event contains diagnostics info. This is useful because a
non-verbose harness may choose to hide events that are not in this
category. Some formatters may choose to send these to STDERR instead of
STDOUT to ensure they are seen.
- $bool = $e->no_display
- False by default. This will return true on events that should not be
displayed by formatters.
- $id = $e->in_subtest
- If the event is inside a subtest this should have the subtest ID.
- $id = $e->subtest_id
- If the event is a final subtest event, this should contain the subtest
ID.
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.
The source code repository for Test2 can be found at
http://github.com/Test-More/test-more/.
- Chad Granum <exodist@cpan.org>
- Chad Granum <exodist@cpan.org>
Copyright 2020 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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