Test2::Transition - phpMan

NAME
    Test2::Transition - Transition notes when upgrading to Test2

DESCRIPTION
    This is where gotchas and breakages related to the Test2 upgrade are
    documented. The upgrade causes Test::Builder to defer to Test2 under the
    hood. This transition is mostly transparent, but there are a few cases
    that can trip you up.

THINGS THAT BREAK
    This is the list of scenarios that break with the new internals.

  Test::Builder1.5/2 conditionals
   The Problem
    a few years back there were two attempts to upgrade/replace
    Test::Builder. Confusingly these were called Test::Builder2 and
    Test::Builder1.5, in that order. Many people put conditionals in their
    code to check the Test::Builder version number and adapt their code
    accordingly.

    The Test::Builder2/1.5 projects both died out. Now the conditional code
    people added has become a mine field. A vast majority of modules broken
    by Test2 fall into this category.

   The Fix
    The fix is to remove all Test::Builder1.5/2 related code. Either use the
    legacy Test::Builder API, or use Test2 directly.

  Replacing the Test::Builder singleton
   The Problem
    Some test modules would replace the Test::Builder singleton instance
    with their own instance or subclass. This was usually done to intercept
    or modify results as they happened.

    The Test::Builder singleton is now a simple compatibility wrapper around
    Test2. The Test::Builder singleton is no longer the central place for
    results. Many results bypass the Test::Builder singleton completely,
    which breaks and behavior intended when replacing the singleton.

   The Fix
    If you simply want to intercept all results instead of letting them go
    to TAP, you should look at the Test2::API docs and read about pushing a
    new hub onto the hub stack. Replacing the hub temporarily is now the
    correct way to intercept results.

    If your goal is purely monitoring of events use the
    "Test2::Hub->listen()" method exported by Test::More to watch events as
    they are fired. If you wish to modify results before they go to TAP look
    at the "Test2::Hub->filter()" method.

  Directly Accessing Hash Elements
   The Problem
    Some modules look directly at hash keys on the Test::Builder singleton.
    The problem here is that the Test::Builder singleton no longer holds
    anything important.

   The Fix
    The fix is to use the API specified in Test2::API to look at or modify
    state as needed.

  Subtest indentation
   The Problem
    An early change, in fact the change that made Test2 an idea, was a
    change to the indentation of the subtest note. It was decided it would
    be more readable to outdent the subtest note instead of having it inline
    with the subtest:

        # subtest foo
            ok 1 - blah
            1..1
        ok 1 - subtest foo

    The old style indented the note:

            # subtest foo
            ok 1 - blah
            1..1
        ok 1 - subtest foo

    This breaks tests that do string comparison of TAP output.

   The Fix
        my $indent = $INC{'Test2/API.pm'} ? '' : '    ';

        is(
            $subtest_output,
            "${indent}# subtest foo",
            "Got subtest note"
        );

    Check if $INC{'Test2/API.pm'} is set, if it is then no indentation
    should be expected. If it is not set, then the old Test::Builder is in
    use, indentation should be expected.

DISTRIBUTIONS THAT BREAK OR NEED TO BE UPGRADED
    This is a list of cpan modules that have been known to have been broken
    by the upgrade at one point.

  WORKS BUT TESTS WILL FAIL
    These modules still function correctly, but their test suites will not
    pass. If you already have these modules installed then you can continue
    to use them. If you are trying to install them after upgrading
    Test::Builder you will need to force installation, or bypass the broken
    tests.

    Test::DBIx::Class::Schema
        This module has a test that appears to work around a Test::Builder
        bug. The bug appears to have been fixed by Test2, which means the
        workaround causes a failure. This can be easily updated, but nobody
        has done so yet.

        Known broken in versions: 1.0.9 and older

    Device::Chip
        Tests break due to subtest indentation.

        Known broken in version 0.07. Apparently works fine in 0.06 though.
        Patch has been submitted to fix the issue.

  UPGRADE SUGGESTED
    These are modules that did not break, but had broken test suites that
    have since been fixed.

    Test::Exception
        Old versions work fine, but have a minor test name behavior that
        breaks with Test2. Old versions will no longer install because of
        this. The latest version on CPAN will install just fine. Upgrading
        is not required, but is recommended.

        Fixed in version: 0.43

    Data::Peek
        Some tests depended on $! and $? being modified in subtle ways. A
        patch was applied to correct things that changed.

        The module itself works fine, there is no need to upgrade.

        Fixed in version: 0.45

    circular::require
        Some tests were fragile and required base.pm to be loaded at a late
        stage. Test2 was loading base.pm too early. The tests were updated
        to fix this.

        The module itself never broke, you do not need to upgrade.

        Fixed in version: 0.12

    Test::Module::Used
        A test worked around a now-fixed planning bug. There is no need to
        upgrade if you have an old version installed. New versions install
        fine if you want them.

        Fixed in version: 0.2.5

    Test::Moose::More
        Some tests were fragile, but have been fixed. The actual breakage
        was from the subtest comment indentation change.

        No need to upgrade, old versions work fine. Only new versions will
        install.

        Fixed in version: 0.025

    Test::FITesque
        This was broken by a bugfix to how planning is done. The test was
        updated after the bugfix.

        Fixed in version: 0.04

    Test::Kit
        Old versions work fine, but would not install because
        Test::Aggregate was in the dependency chain. An upgrade should not
        be needed.

        Fixed in version: 2.15

    autouse
        A test broke because it depended on Scalar::Util not being loaded.
        Test2 loads Scalar::Util. The test was updated to load Test2 after
        checking Scalar::Util's load status.

        There is no need to upgrade if you already have it installed.

        Fixed in version: 1.11

  NEED TO UPGRADE
    Test::SharedFork
        Old versions need to directly access Test::Builder singleton hash
        elements. The latest version on CPAN will still do this on old
        Test::Builder, but will defer to Test2::IPC on Test2.

        Fixed in version: 0.35

    Test::Builder::Clutch
        This works by doing overriding methods on the singleton, and
        directly accessing hash values on the singleton. A new version has
        been released that uses the Test2 API to accomplish the same result
        in a saner way.

        Fixed in version: 0.07

    Test::Dist::VersionSync
        This had Test::Builder2 conditionals. This was fixed by removing the
        conditionals.

        Fixed in version: 1.1.4

    Test::Modern
        This relied on "Test::Builder->_try()" which was a private method,
        documented as something nobody should use. This was fixed by using a
        different tool.

        Fixed in version: 0.012

    Test::UseAllModules
        Version 0.14 relied on "Test::Builder->history" which was available
        in Test::Builder 1.5. Versions 0.12 and 0.13 relied on other
        Test::Builder internals.

        Fixed in version: 0.15

    Test::More::Prefix
        Worked by applying a role that wrapped
        "Test::Builder->_print_comment". Fixed by adding an event filter
        that modifies the message instead when running under Test2.

        Fixed in version: 0.007

  STILL BROKEN
    Test::Aggregate
        This distribution directly accesses the hash keys in the
        Test::Builder singleton. It also approaches the problem from the
        wrong angle, please consider using Test2::Aggregate for similar
        functionality and Test2::Harness which allows module preloading at
        the harness level.

        Still broken as of version: 0.373

    Test::Wrapper
        This module directly uses hash keys in the Test::Builder singleton.
        This module is also obsolete thanks to the benefits of Test2. Use
        "intercept()" from Test2::API to achieve a similar result.

        Still broken as of version: 0.3.0

    Test::ParallelSubtest
        This module overrides "Test::Builder::subtest()" and
        "Test::Builder::done_testing()". It also directly accesses hash
        elements of the singleton. It has not yet been fixed.

        Alternatives: Test2::AsyncSubtest and Test2::Workflow (not stable).

        Still broken as of version: 0.05

    Test::Pretty
        See https://github.com/tokuhirom/Test-Pretty/issues/25

        The author admits the module is crazy, and he is awaiting a stable
        release of something new (Test2) to completely rewrite it in a sane
        way.

        Still broken as of version: 0.32

    Net::BitTorrent
        The tests for this module directly access Test::Builder hash keys.
        Most, if not all of these hash keys have public API methods that
        could be used instead to avoid the problem.

        Still broken in version: 0.052

    Test::Group
        It monkeypatches Test::Builder, and calls it "black magic" in the
        code.

        Still broken as of version: 0.20

    Test::Flatten
        This modifies the Test::Builder internals in many ways. A better was
        to accomplish the goal of this module is to write your own subtest
        function.

        Still broken as of version: 0.11

    Log::Dispatch::Config::TestLog
        Modifies Test::Builder internals.

        Still broken as of version: 0.02

    Test::Able
        Modifies Test::Builder internals.

        Still broken as of version: 0.11

MAKE ASSERTIONS -> SEND EVENTS
  LEGACY
        use Test::Builder;

        # A majority of tools out there do this:
        # my $TB = Test::Builder->new;
        # This works, but has always been wrong, forcing Test::Builder to implement
        # subtests as a horrific hack. It also causes problems for tools that try
        # to replace the singleton (also discouraged).

        sub my_ok($;$) {
            my ($bool, $name) = @_;
            my $TB = Test::Builder->new;
            $TB->ok($bool, $name);
        }

        sub my_diag($) {
            my ($msg) = @_;
            my $TB = Test::Builder->new;
            $TB->diag($msg);
        }

  TEST2
        use Test2::API qw/context/;

        sub my_ok($;$) {
            my ($bool, $name) = @_;
            my $ctx = context();
            $ctx->ok($bool, $name);
            $ctx->release;
        }

        sub my_diag($) {
            my ($msg) = @_;
            my $ctx = context();
            $ctx->diag($msg);
            $ctx->release;
        }

    The context object has API compatible implementations of the following
    methods:

    ok($bool, $name)
    diag(@messages)
    note(@messages)
    subtest($name, $code)

    If you are looking for helpers with "is", "like", and others, see
    Test2::Suite.

WRAP EXISTING TOOLS
  LEGACY
        use Test::More;

        sub exclusive_ok {
            my ($bool1, $bool2, $name) = @_;

            # Ensure errors are reported 1 level higher
            local $Test::Builder::Level = $Test::Builder::Level + 1;

            $ok = $bool1 || $bool2;
            $ok &&= !($bool1 && $bool2);
            ok($ok, $name);

            return $bool;
        }

    Every single tool in the chain from this, to "ok", to anything "ok"
    calls needs to increment the $Level variable. When an error occurs
    Test::Builder will do a trace to the stack frame determined by $Level,
    and report that file+line as the one where the error occurred. If you or
    any other tool you use forgets to set $Level then errors will be
    reported to the wrong place.

  TEST2
        use Test::More;

        sub exclusive_ok {
            my ($bool1, $bool2, $name) = @_;

            # Grab and store the context, even if you do not need to use it
            # directly.
            my $ctx = context();

            $ok = $bool1 || $bool2;
            $ok &&= !($bool1 && $bool2);
            ok($ok, $name);

            $ctx->release;
            return $bool;
        }

    Instead of using $Level to perform a backtrace, Test2 uses a context
    object. In this sample you create a context object and store it. This
    locks the context (errors report 1 level up from here) for all wrapped
    tools to find. You do not need to use the context object, but you do
    need to store it in a variable. Once the sub ends the $ctx variable is
    destroyed which lets future tools find their own.

USING UTF8
  LEGACY
        # Set the mode BEFORE anything loads Test::Builder
        use open ':std', ':encoding(utf8)';
        use Test::More;

    Or

        # Modify the filehandles
        my $builder = Test::More->builder;
        binmode $builder->output,         ":encoding(utf8)";
        binmode $builder->failure_output, ":encoding(utf8)";
        binmode $builder->todo_output,    ":encoding(utf8)";

  TEST2
        use Test2::API qw/test2_stack/;

        test2_stack->top->format->encoding('utf8');

    Though a much better way is to use the Test2::Plugin::UTF8 plugin, which
    is part of Test2::Suite.

AUTHORS, CONTRIBUTORS AND REVIEWERS
    The following people have all contributed to this document in some way,
    even if only for review.

    Chad Granum (EXODIST) <exodist AT cpan.org>

SOURCE
    The source code repository for Test2 can be found at
    http://github.com/Test-More/test-more/.

MAINTAINER
    Chad Granum <exodist AT cpan.org>

COPYRIGHT
    Copyright 2020 Chad Granum <exodist AT cpan.org>.

    This program is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself.

    See http://www.perl.com/perl/misc/Artistic.html