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Ovid (2709)

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Stuff with the Perl Foundation. A couple of patches in the Perl core. A few CPAN modules. That about sums it up.

Journal of Ovid (2709)

Sunday January 13, 2008
12:14 PM

Test::Most -- Most commonly needed test functions and featur

[ #35381 ]

Not everyone is happy with this, but you might like it. It's on its way to the CPAN now.

    Test::Most - Most commonly needed test functions and features.

    Version 0.01

    WARNING: This is alpha code. It seems to work well, but use with

    This module provides you with the most commonly used testing functions
    and gives you a bit more fine-grained control over your test suite.

        use Test::Most tests => 4, 'die';

        ok 1, 'Normal calls to ok() should succeed';
        is 2, 2, '... as should all passing tests';
        eq_or_diff [3], [4], '... but failing tests should die';
        ok 4, '... will never get to here';

    As you can see, the "eq_or_diff" test will fail. Because 'die' is in the
    import list, the test program will halt at that point.

    All functions from the following modules will automatically be exported
    into your namespace:

    * "Test::More"
    * "Test::Exception"
    * "Test::Differences"
    * "Test::Deep"

    Functions which are *optionally* exported from any of those modules must
    be referred to by their fully-qualified name:

      Test::Deep::render_stack( $var, $stack );

    Four other functions are also automatically exported:

     is_deeply $foo, bar, '... we die if this fails';

    This function, if called, will cause the test program to die if any
    tests fail after it.

     is_deeply $foo, bar, '... we bail out if this fails';

    This function, if called, will cause the test suite to BAIL_OUT() if any
    tests fail after it.

     is_deeply $foo, bar, '... we die if this fails';

     cmp_bag(\@got, \@bag, '... we will not die if this fails';

    This restores the original test failure behavior, so subsequent tests
    will no longer die or BAIL_OUT().

    Like "diag()", but only outputs the message if $ENV{TEST_VERBOSE} is
    set. This is typically set by using the "-v" switch with "prove".

    Requires "Test::Harness" 3.07 or greater.

    Sometimes you want your test suite to die or BAIL_OUT() if a test fails.
    In order to provide maximum flexibility, there are three ways to
    accomplish each of these.

  Import list
     use Test::Most 'die', tests => 7;
     use Test::Most qw< no_plan bail >;

    If "die" or "bail" is anywhere in the import list, the test
    program/suite will "die" or "BAIL_OUT()" as appropriate the first time a
    test fails. Calling "restore_fail" anywhere in the test program will
    restore the original behavior (not dieing or bailing out).

     use Test::Most 'no_plan;
     ok $bar, 'The test suite will continue if this passes';

     is_deeply $foo, bar, '... we die if this fails';

     ok $baz, 'The test suite will continue if this passes';

    The "die_on_fail" and "bail_on_fail" functions will automatically set
    the desired behavior at runtime.

  Environment variables
     DIE_ON_FAIL=1 prove t/
     BAIL_ON_FAIL=1 prove t/

    If the "DIE_ON_FAIL" or "BAIL_ON_FAIL" environment variables are true,
    any tests which use "Test::Most" will die or call BAIL_OUT on test

    People want more control over their test suites. Sometimes when you see
    hundreds of tests failing and whizzing by, you want the test suite to
    simply halt on the first failure. This module gives you that control.

    As for the reasons for the four test modules chosen, I ran code over a
    local copy of the CPAN to find the most commonly used testing modules.
    Here were the top ten (out of 287):

     Test::More              44461
     Test                     8937
     Test::Exception          1379
     Test::Simple              731
     Test::Base                316
     Test::Builder::Tester     193
     Test::NoWarnings          174
     Test::Differences         146
     Test::MockObject          139
     Test::Deep                127

    The four modules chosen seemed the best fit for what "Test::Most" is
    trying to do.

    Curtis "Ovid" Poe, "<ovid at>"

    Please report any bugs or feature requests to "bug-test-extended at", or through the web interface at
    <>. I will be
    notified, and then you'll automatically be notified of progress on your
    bug as I make changes.

    You can find documentation for this module with the perldoc command.

        perldoc Test::Most

    You can also look for information at:

    * RT: CPAN's request tracker

    * AnnoCPAN: Annotated CPAN documentation

    * CPAN Ratings

    * Search CPAN

  Deferred plans
    Sometimes you don't know the number of tests you will run when you use
    "Test::More". The "plan()" function allows you to delay specifying the
    plan, but you must still call it before the tests are run. This is an

     use Test::More;

     my $tests = 0;
     foreach my $test (
         my $count = run($test); # assumes tests are being run
         $tests += $count;

    The way around this is typically to use 'no_plan' and when the tests are
    done, "Test::Builder" merely sets the plan to the number of tests run.
    We'd like for the programmer to specify this number instead of letting
    "Test::Builder" do it. However, "Test::Builder" internals are a bit
    difficult to work with, so we're delaying this feature.

  Cleaner skip()
     if ( $some_condition ) {
         skip $message, $num_tests;
     else {
         # run those tests

    That would be cleaner and I might add it if enough people want it.

    Because of how Perl handles arguments, and because diagnostics are not
    really part of the Test Anything Protocol, what actually happens
    internally is that we note that a test has failed and we die or bail out
    as soon as the *next* test is called (but before it runs). This means
    that its arguments are automatically evaulated before we can take

     use Test::Most qw<no_plan die>;

     ok $foo, 'Die if this fails';
     ok factorial(123456), '... but wait a loooong time before you die';

    Many thanks to "perl-qa" for arguing about this so much that I just went
    ahead and did it :)

    Thanks to Aristotle for suggesting a better way to die or bailout.

    Thanks to Smylers for the name.

    Copyright 2008 Curtis "Ovid" Poe, all rights reserved.

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

The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
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  • It would be useful to be able to set bail/fail from the command line, when running prove.

    How about an env variable? (I guess new command line options for prove are out of the question).
    • Sorry, sloppy reading on my part. Funnily enough, just glancing at the Perlmonks post made me see the environment vars, I missed it on this page.
  • Looks great, Ovid. Thanks for releasing this.