test::more.3

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Sometimes running a test under certain conditions will cause the
test script to die.  A certain function or method isn't implemented
(such as \fIfork()\fR on MacOS), some resource isn't available (like a 
net connection) or a module isn't available.  In these cases it's
necessary to skip tests, or declare that they are supposed to fail
but will work in the future (a todo test).
.PP
For more details on the mechanics of skip and todo tests see
Test::Harness.
.PP
The way Test::More handles this is with a named block.  Basically, a
block of tests which can be skipped over or made todo.  It's best if I
just show you...
.IP "\fB\s-1SKIP:\s0 \s-1BLOCK\s0\fR" 4
.IX Item "SKIP: BLOCK"
.Vb 2
\&  SKIP: {
\&      skip $why, $how_many if $condition;
\&
\&      ...normal testing code goes here...
\&  }
.Ve
.Sp
This declares a block of tests that might be skipped, \f(CW$how_many\fR tests
there are, \f(CW$why\fR and under what \f(CW$condition\fR to skip them.  An example is
the easiest way to illustrate:
.Sp
.Vb 2
\&    SKIP: {
\&        eval { require HTML::Lint };
\&
\&        skip "HTML::Lint not installed", 2 if $@;
\&
\&        my $lint = new HTML::Lint;
\&        isa_ok( $lint, "HTML::Lint" );
\&
\&        $lint\->parse( $html );
\&        is( $lint\->errors, 0, "No errors found in HTML" );
\&    }
.Ve
.Sp
If the user does not have HTML::Lint installed, the whole block of
code \fIwon't be run at all\fR.  Test::More will output special ok's
which Test::Harness interprets as skipped, but passing, tests.
.Sp
It's important that \f(CW$how_many\fR accurately reflects the number of tests
in the \s-1SKIP\s0 block so the # of tests run will match up with your plan.
If your plan is \f(CW\*(C`no_plan\*(C'\fR \f(CW$how_many\fR is optional and will default to 1.
.Sp
It's perfectly safe to nest \s-1SKIP\s0 blocks.  Each \s-1SKIP\s0 block must have
the label \f(CW\*(C`SKIP\*(C'\fR, or Test::More can't work its magic.
.Sp
You don't skip tests which are failing because there's a bug in your
program, or for which you don't yet have code written.  For that you
use \s-1TODO\s0.  Read on.
.IP "\fB\s-1TODO:\s0 \s-1BLOCK\s0\fR" 4
.IX Item "TODO: BLOCK"
.Vb 2
\&    TODO: {
\&        local $TODO = $why if $condition;
\&
\&        ...normal testing code goes here...
\&    }
.Ve
.Sp
Declares a block of tests you expect to fail and \f(CW$why\fR.  Perhaps it's
because you haven't fixed a bug or haven't finished a new feature:
.Sp
.Vb 2
\&    TODO: {
\&        local $TODO = "URI::Geller not finished";
\&
\&        my $card = "Eight of clubs";
\&        is( URI::Geller\->your_card, $card, \*(AqIs THIS your card?\*(Aq );
\&
\&        my $spoon;
\&        URI::Geller\->bend_spoon;
\&        is( $spoon, \*(Aqbent\*(Aq,    "Spoon bending, that\*(Aqs original" );
\&    }
.Ve
.Sp
With a todo block, the tests inside are expected to fail.  Test::More
will run the tests normally, but print out special flags indicating
they are \*(L"todo\*(R".  Test::Harness will interpret failures as being ok.
Should anything succeed, it will report it as an unexpected success.
You then know the thing you had todo is done and can remove the
\&\s-1TODO\s0 flag.
.Sp
The nice part about todo tests, as opposed to simply commenting out a
block of tests, is it's like having a programmatic todo list.  You know
how much work is left to be done, you're aware of what bugs there are,
and you'll know immediately when they're fixed.
.Sp
Once a todo test starts succeeding, simply move it outside the block.
When the block is empty, delete it.
.Sp
\&\fB\s-1NOTE\s0\fR: \s-1TODO\s0 tests require a Test::Harness upgrade else it will
treat it as a normal failure.  See \*(L"\s-1CAVEATS\s0 and \s-1NOTES\s0\*(R").
.IP "\fBtodo_skip\fR" 4
.IX Item "todo_skip"
.Vb 2
\&    TODO: {
\&        todo_skip $why, $how_many if $condition;
\&
\&        ...normal testing code...
\&    }
.Ve
.Sp
With todo tests, it's best to have the tests actually run.  That way
you'll know when they start passing.  Sometimes this isn't possible.
Often a failing test will cause the whole program to die or hang, even
inside an \f(CW\*(C`eval BLOCK\*(C'\fR with and using \f(CW\*(C`alarm\*(C'\fR.  In these extreme
cases you have no choice but to skip over the broken tests entirely.
.Sp
The syntax and behavior is similar to a \f(CW\*(C`SKIP: BLOCK\*(C'\fR except the
tests will be marked as failing but todo.  Test::Harness will
interpret them as passing.
.IP "When do I use \s-1SKIP\s0 vs. \s-1TODO\s0?" 4
.IX Item "When do I use SKIP vs. TODO?"
\&\fBIf it's something the user might not be able to do\fR, use \s-1SKIP\s0.
This includes optional modules that aren't installed, running under
an \s-1OS\s0 that doesn't have some feature (like \fIfork()\fR or symlinks), or maybe
you need an Internet connection and one isn't available.
.Sp
\&\fBIf it's something the programmer hasn't done yet\fR, use \s-1TODO\s0.  This
is for any code you haven't written yet, or bugs you have yet to fix,
but want to put tests in your testing script (always a good idea).
.Sh "Test control"
.IX Subsection "Test control"
.IP "\fB\s-1BAIL_OUT\s0\fR" 4
.IX Item "BAIL_OUT"
.Vb 1
\&    BAIL_OUT($reason);
.Ve
.Sp
Indicates to the harness that things are going so badly all testing
should terminate.  This includes the running any additional test scripts.
.Sp
This is typically used when testing cannot continue such as a critical
module failing to compile or a necessary external utility not being
available such as a database connection failing.
.Sp
The test will exit with 255.
.Sh "Discouraged comparison functions"
.IX Subsection "Discouraged comparison functions"
The use of the following functions is discouraged as they are not
actually testing functions and produce no diagnostics to help figure
out what went wrong.  They were written before \fIis_deeply()\fR existed
because I couldn't figure out how to display a useful diff of two
arbitrary data structures.
.PP
These functions are usually used inside an \fIok()\fR.
.PP
.Vb 1
\&    ok( eq_array(\e@got, \e@expected) );
.Ve
.PP
\&\f(CW\*(C`is_deeply()\*(C'\fR can do that better and with diagnostics.
.PP
.Vb 1
\&    is_deeply( \e@got, \e@expected );
.Ve
.PP
They may be deprecated in future versions.
.IP "\fBeq_array\fR" 4
.IX Item "eq_array"
.Vb 1
\&  my $is_eq = eq_array(\e@got, \e@expected);
.Ve
.Sp
Checks if two arrays are equivalent.  This is a deep check, so
multi-level structures are handled correctly.
.IP "\fBeq_hash\fR" 4
.IX Item "eq_hash"
.Vb 1
\&  my $is_eq = eq_hash(\e%got, \e%expected);
.Ve
.Sp
Determines if the two hashes contain the same keys and values.  This
is a deep check.
.IP "\fBeq_set\fR" 4
.IX Item "eq_set"
.Vb 1
\&  my $is_eq = eq_set(\e@got, \e@expected);
.Ve
.Sp
Similar to \fIeq_array()\fR, except the order of the elements is \fBnot\fR
important.  This is a deep check, but the irrelevancy of order only
applies to the top level.
.Sp
.Vb 1
\&    ok( eq_set(\e@got, \e@expected) );
.Ve
.Sp
Is better written:
.Sp
.Vb 1
\&    is_deeply( [sort @got], [sort @expected] );
.Ve
.Sp
\&\fB\s-1NOTE\s0\fR By historical accident, this is not a true set comparison.
While the order of elements does not matter, duplicate elements do.
.Sp
\&\fB\s-1NOTE\s0\fR \fIeq_set()\fR does not know how to deal with references at the top
level.  The following is an example of a comparison which might not work:
.Sp
.Vb 1
\&    eq_set([\e1, \e2], [\e2, \e1]);
.Ve
.Sp
Test::Deep contains much better set comparison functions.
.Sh "Extending and Embedding Test::More"
.IX Subsection "Extending and Embedding Test::More"
Sometimes the Test::More interface isn't quite enough.  Fortunately,
Test::More is built on top of Test::Builder which provides a single,
unified backend for any test library to use.  This means two test
libraries which both use Test::Builder \fBcan be used together in the
same program\fR.
.PP
If you simply want to do a little tweaking of how the tests behave,
you can access the underlying Test::Builder object like so:
.IP "\fBbuilder\fR" 4
.IX Item "builder"
.Vb 1
\&    my $test_builder = Test::More\->builder;
.Ve
.Sp
Returns the Test::Builder object underlying Test::More for you to play
with.
.SH "EXIT CODES"
.IX Header "EXIT CODES"
If all your tests passed, Test::Builder will exit with zero (which is
normal).  If anything failed it will exit with how many failed.  If
you run less (or more) tests than you planned, the missing (or extras)
will be considered failures.  If no tests were ever run Test::Builder
will throw a warning and exit with 255.  If the test died, even after
having successfully completed all its tests, it will still be
considered a failure and will exit with 255.
.PP
So the exit codes are...
.PP
.Vb 3
\&    0                   all tests successful
\&    255                 test died or all passed but wrong # of tests run
\&    any other number    how many failed (including missing or extras)
.Ve
.PP
If you fail more than 254 tests, it will be reported as 254.
.PP
\&\fB\s-1NOTE\s0\fR  This behavior may go away in future versions.
.SH "CAVEATS and NOTES"
.IX Header "CAVEATS and NOTES"
.IP "Backwards compatibility" 4
.IX Item "Backwards compatibility"
Test::More works with Perls as old as 5.004_05.
.IP "Overloaded objects" 4
.IX Item "Overloaded objects"
String overloaded objects are compared \fBas strings\fR (or in \fIcmp_ok()\fR's
case, strings or numbers as appropriate to the comparison op).  This
prevents Test::More from piercing an object's interface allowing
better blackbox testing.  So if a function starts returning overloaded
objects instead of bare strings your tests won't notice the
difference.  This is good.
.Sp
However, it does mean that functions like \fIis_deeply()\fR cannot be used to
test the internals of string overloaded objects.  In this case I would
suggest Test::Deep which contains more flexible testing functions for
complex data structures.
.IP "Threads" 4
.IX Item "Threads"
Test::More will only be aware of threads if \*(L"use threads\*(R" has been done
\&\fIbefore\fR Test::More is loaded.  This is ok:
.Sp
.Vb 2
\&    use threads;
\&    use Test::More;
.Ve
.Sp
This may cause problems:
.Sp
.Vb 2
\&    use Test::More
\&    use threads;
.Ve
.Sp
5.8.1 and above are supported.  Anything below that has too many bugs.
.IP "Test::Harness upgrade" 4
.IX Item "Test::Harness upgrade"
no_plan and todo depend on new Test::Harness features and fixes.  If
you're going to distribute tests that use no_plan or todo your
end-users will have to upgrade Test::Harness to the latest one on
\&\s-1CPAN\s0.  If you avoid no_plan and \s-1TODO\s0 tests, the stock Test::Harness
will work fine.
.Sp
Installing Test::More should also upgrade Test::Harness.
.SH "HISTORY"
.IX Header "HISTORY"
This is a case of convergent evolution with Joshua Pritikin's Test
module.  I was largely unaware of its existence when I'd first
written my own \fIok()\fR routines.  This module exists because I can't
figure out how to easily wedge test names into Test's interface (along
with a few other problems).
.PP
The goal here is to have a testing utility that's simple to learn,
quick to use and difficult to trip yourself up with while still
providing more flexibility than the existing Test.pm.  As such, the
names of the most common routines are kept tiny, special cases and
magic side-effects are kept to a minimum.  \s-1WYSIWYG\s0.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
Test::Simple if all this confuses you and you just want to write
some tests.  You can upgrade to Test::More later (it's forward
compatible).
.PP
Test is the old testing module.  Its main benefit is that it has
been distributed with Perl since 5.004_05.
.PP
Test::Harness for details on how your test results are interpreted
by Perl.
.PP
Test::Differences for more ways to test complex data structures.
And it plays well with Test::More.
.PP
Test::Class is like XUnit but more perlish.
.PP
Test::Deep gives you more powerful complex data structure testing.
.PP
Test::Unit is XUnit style testing.
.PP
Test::Inline shows the idea of embedded testing.
.PP
Bundle::Test installs a whole bunch of useful test modules.
.SH "AUTHORS"
.IX Header "AUTHORS"
Michael G Schwern <[e-mail]> with much inspiration
from Joshua Pritikin's Test module and lots of help from Barrie
Slaymaker, Tony Bowden, blackstar.co.uk, chromatic, Fergal Daly and
the perl-qa gang.
.SH "BUGS"
.IX Header "BUGS"
See \fIhttp://rt.cpan.org\fR to report and view bugs.
.SH "COPYRIGHT"
.IX Header "COPYRIGHT"
Copyright 2001\-2002, 2004\-2006 by Michael G Schwern <[e-mail]>.
.PP
This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.
.PP
See \fIhttp://www.perl.com/perl/misc/Artistic.html\fR