Test documentation.

  use strict;
  use Test;

  # use a BEGIN block so we print our plan before MyModule is loaded
  BEGIN { plan tests => 14, todo => [3,4] }

  # load your module...
  use MyModule;

  ok(0); # failure
  ok(1); # success

  ok(0); # ok, expected failure (see todo list, above)
  ok(1); # surprise success!

  ok(0,1);             # failure: '0' ne '1'
  ok('broke','fixed'); # failure: 'broke' ne 'fixed'
  ok('fixed','fixed'); # success: 'fixed' eq 'fixed'
  ok('fixed',qr/x/);   # success: 'fixed' =~ qr/x/

  ok(sub { 1+1 }, 2);  # success: '2' eq '2'
  ok(sub { 1+1 }, 3);  # failure: '2' ne '3'
  ok(0, int(rand(2));  # (just kidding :-)

  my @list = (0,0);
  ok @list, 3, "\@list=".join(',',@list);      #extra diagnostics
  ok 'segmentation fault', '/(?i)success/';    #regex match

  skip($feature_is_missing, ...);    #do platform specific test

sub ok {

($;$$) {    croak "ok: plan before you test!" if !$planned;
    my ($pkg,$file,$line) = caller($TestLevel);
    my $repetition = ++$history{"$file:$line"};
    my $context = ("$file at line $line".
		   ($repetition > 1 ? " fail\# $repetition" : ''));
    my $ok=0;
    my $result = to_value(shift);
    my ($expected,$diag);
    if (@_ == 0) {
	$ok = $result;
    } else {
	$expected = to_value(shift);
	my ($regex,$ignore);
	if (!defined $expected) {
	    $ok = !defined $result;
	} elsif (!defined $result) {
	    $ok = 0;
	} elsif ((ref($expected)||'') eq 'Regexp') {
	    $ok = $result =~ /$expected/;
	} elsif (($regex) = ($expected =~ m,^ / (.+) / $,sx) or
	    ($ignore, $regex) = ($expected =~ m,^ m([^\w\s]) (.+) \1 $,sx)) {
	    $ok = $result =~ /$regex/;
	} else {
	    $ok = $result eq $expected;
	}
    }
    my $todo = $todo{$ntest};
    if ($todo and $ok) {
	$context .= ' TODO?!' if $todo;
	print $TESTOUT "ok $ntest # ($context)\n";
    } else {
	print $TESTOUT "not " if !$ok;
	print $TESTOUT "ok $ntest\n";
	
	if (!$ok) {
	    my $detail = { 'repetition' => $repetition, 'package' => $pkg,
			   'result' => $result, 'todo' => $todo };
	    $$detail{expected} = $expected if defined $expected;
	    $diag = $$detail{diagnostic} = to_value(shift) if @_;
	    $context .= ' *TODO*' if $todo;
	    if (!defined $expected) {
		if (!$diag) {
		    print $TESTOUT "# Failed test $ntest in $context\n";
		} else {
		    print $TESTOUT "# Failed test $ntest in $context: $diag\n";
		}
	    } else {
		my $prefix = "Test $ntest";
		print $TESTOUT "# $prefix got: ".
		    (defined $result? "'$result'":'<UNDEF>')." ($context)\n";
		$prefix = ' ' x (length($prefix) - 5);
		if ((ref($expected)||'') eq 'Regexp') {
		    $expected = 'qr/'.$expected.'/'
		} else {
		    $expected = "'$expected'";
		}
		if (!$diag) {
		    print $TESTOUT "# $prefix Expected: $expected\n";
		} else {
		    print $TESTOUT "# $prefix Expected: $expected ($diag)\n";
		}
	    }
	    push @FAILDETAIL, $detail;
	}
    }
    ++ $ntest;
    $ok;

}

sub plan {

    croak "Test::plan(%args): odd number of arguments" if @_ & 1;
    croak "Test::plan(): should not be called more than once" if $planned;
    my $max=0;
    for (my $x=0; $x < @_; $x+=2) {
	my ($k,$v) = @_[$x,$x+1];
	if ($k =~ /^test(s)?$/) { $max = $v; }
	elsif ($k eq 'todo' or 
	       $k eq 'failok') { for (@$v) { $todo{$_}=1; }; }
	elsif ($k eq 'onfail') { 
	    ref $v eq 'CODE' or croak "Test::plan(onfail => $v): must be CODE";
	    $ONFAIL = $v; 
	}
	else { carp "Test::plan(): skipping unrecognized directive '$k'" }
    }
    my @todo = sort { $a <=> $b } keys %todo;
    if (@todo) {
	print $TESTOUT "1..$max todo ".join(' ', @todo).";\n";
    } else {
	print $TESTOUT "1..$max\n";
    }
    ++$planned;

}

sub skip {

($$;$$) {    my $whyskip = to_value(shift);
    if ($whyskip) {
	$whyskip = 'skip' if $whyskip =~ m/^\d+$/;
	print $TESTOUT "ok $ntest # $whyskip\n";
	++ $ntest;
	1;
    } else {
	local($TestLevel) = $TestLevel+1;  #ignore this stack frame
	&ok;
    }
}

END {
    $ONFAIL->(\@FAILDETAIL) if @FAILDETAIL && $ONFAIL;
}

1;
__END__

}

* NORMAL TESTS

These tests are expected to succeed. If they don't something's
screwed up!

* SKIPPED TESTS

Skip is for tests that might or might not be possible to run depending
on the availability of platform specific features. The first argument
should evaluate to true (think "yes, please skip") if the required
feature is not available. After the first argument, skip works
exactly the same way as do normal tests.

* TODO TESTS

TODO tests are designed for maintaining an executable TODO list.
These tests are expected NOT to succeed. If a TODO test does succeed,
the feature in question should not be on the TODO list, now should it?
Packages should NOT be released with succeeding TODO tests. As soon
as a TODO test starts working, it should be promoted to a normal test
and the newly working feature should be documented in the release
notes or change log.

  BEGIN { plan test => 4, onfail => sub { warn "CALL 911!" } }

While test failures should be enough, extra diagnostics can be
triggered at the end of a test run. onfail is passed an array ref
of hash refs that describe each test failure. Each hash will contain
at least the following fields: package, repetition, and
result. (The file, line, and test number are not included because
their correspondence to a particular test is tenuous.) If the test
had an expected value or a diagnostic string, these will also be
included.
The optional onfail hook might be used simply to print out the
version of your package and/or how to report problems. It might also
be used to generate extremely sophisticated diagnostics for a
particularly bizarre test failure. However it's not a panacea. Core
dumps or other unrecoverable errors prevent the onfail hook from
running. (It is run inside an END block.) Besides, onfail is
probably over-kill in most cases. (Your test code should be simpler
than the code it is testing, yes?)

ok	No description	Code
plan	No description	Code
skip	No description	Code
to_value	No description	Code