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authorNorbert Preining <norbert@preining.info>2019-09-02 13:46:59 +0900
committerNorbert Preining <norbert@preining.info>2019-09-02 13:46:59 +0900
commite0c6872cf40896c7be36b11dcc744620f10adf1d (patch)
tree60335e10d2f4354b0674ec22d7b53f0f8abee672 /systems/texlive/tlnet/tlpkg/tlperl/lib/Test.pm
Initial commit
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+
+require 5.004;
+package Test;
+
+use strict;
+
+use Carp;
+our ($VERSION, @ISA, @EXPORT, @EXPORT_OK, $ntest, $TestLevel); #public-is
+our ($TESTOUT, $TESTERR, %Program_Lines, $told_about_diff,
+ $ONFAIL, %todo, %history, $planned, @FAILDETAIL); #private-ish
+
+# In case a test is run in a persistent environment.
+sub _reset_globals {
+ %todo = ();
+ %history = ();
+ @FAILDETAIL = ();
+ $ntest = 1;
+ $TestLevel = 0; # how many extra stack frames to skip
+ $planned = 0;
+}
+
+$VERSION = '1.31';
+require Exporter;
+@ISA=('Exporter');
+
+@EXPORT = qw(&plan &ok &skip);
+@EXPORT_OK = qw($ntest $TESTOUT $TESTERR);
+
+$|=1;
+$TESTOUT = *STDOUT{IO};
+$TESTERR = *STDERR{IO};
+
+# Use of this variable is strongly discouraged. It is set mainly to
+# help test coverage analyzers know which test is running.
+$ENV{REGRESSION_TEST} = $0;
+
+
+=head1 NAME
+
+Test - provides a simple framework for writing test scripts
+
+=head1 SYNOPSIS
+
+ 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;
+
+ # Helpful notes. All note-lines must start with a "#".
+ print "# I'm testing MyModule version $MyModule::VERSION\n";
+
+ 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'
+
+ my @list = (0,0);
+ ok @list, 3, "\@list=".join(',',@list); #extra notes
+ ok 'segmentation fault', '/(?i)success/'; #regex match
+
+ skip(
+ $^O =~ m/MSWin/ ? "Skip if MSWin" : 0, # whether to skip
+ $foo, $bar # arguments just like for ok(...)
+ );
+ skip(
+ $^O =~ m/MSWin/ ? 0 : "Skip unless MSWin", # whether to skip
+ $foo, $bar # arguments just like for ok(...)
+ );
+
+=head1 DESCRIPTION
+
+This module simplifies the task of writing test files for Perl modules,
+such that their output is in the format that
+L<Test::Harness|Test::Harness> expects to see.
+
+=head1 QUICK START GUIDE
+
+To write a test for your new (and probably not even done) module, create
+a new file called F<t/test.t> (in a new F<t> directory). If you have
+multiple test files, to test the "foo", "bar", and "baz" feature sets,
+then feel free to call your files F<t/foo.t>, F<t/bar.t>, and
+F<t/baz.t>
+
+=head2 Functions
+
+This module defines three public functions, C<plan(...)>, C<ok(...)>,
+and C<skip(...)>. By default, all three are exported by
+the C<use Test;> statement.
+
+=over 4
+
+=item C<plan(...)>
+
+ BEGIN { plan %theplan; }
+
+This should be the first thing you call in your test script. It
+declares your testing plan, how many there will be, if any of them
+should be allowed to fail, and so on.
+
+Typical usage is just:
+
+ use Test;
+ BEGIN { plan tests => 23 }
+
+These are the things that you can put in the parameters to plan:
+
+=over
+
+=item C<tests =E<gt> I<number>>
+
+The number of tests in your script.
+This means all ok() and skip() calls.
+
+=item C<todo =E<gt> [I<1,5,14>]>
+
+A reference to a list of tests which are allowed to fail.
+See L</TODO TESTS>.
+
+=item C<onfail =E<gt> sub { ... }>
+
+=item C<onfail =E<gt> \&some_sub>
+
+A subroutine reference to be run at the end of the test script, if
+any of the tests fail. See L</ONFAIL>.
+
+=back
+
+You must call C<plan(...)> once and only once. You should call it
+in a C<BEGIN {...}> block, like so:
+
+ BEGIN { plan tests => 23 }
+
+=cut
+
+sub plan {
+ croak "Test::plan(%args): odd number of arguments" if @_ & 1;
+ croak "Test::plan(): should not be called more than once" if $planned;
+
+ local($\, $,); # guard against -l and other things that screw with
+ # print
+
+ _reset_globals();
+
+ _read_program( (caller)[1] );
+
+ my $max=0;
+ while (@_) {
+ my ($k,$v) = splice(@_, 0, 2);
+ if ($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;
+ print $TESTOUT "# Running under perl version $] for $^O",
+ (chr(65) eq 'A') ? "\n" : " in a non-ASCII world\n";
+
+ print $TESTOUT "# Win32::BuildNumber ", &Win32::BuildNumber(), "\n"
+ if defined(&Win32::BuildNumber) and defined &Win32::BuildNumber();
+
+ print $TESTOUT "# MacPerl version $MacPerl::Version\n"
+ if defined $MacPerl::Version;
+
+ printf $TESTOUT
+ "# Current time local: %s\n# Current time GMT: %s\n",
+ scalar(localtime($^T)), scalar(gmtime($^T));
+
+ print $TESTOUT "# Using Test.pm version $VERSION\n";
+
+ # Retval never used:
+ return undef;
+}
+
+sub _read_program {
+ my($file) = shift;
+ return unless defined $file and length $file
+ and -e $file and -f _ and -r _;
+ open(SOURCEFILE, '<', $file) || return;
+ $Program_Lines{$file} = [<SOURCEFILE>];
+ close(SOURCEFILE);
+
+ foreach my $x (@{$Program_Lines{$file}})
+ { $x =~ tr/\cm\cj\n\r//d }
+
+ unshift @{$Program_Lines{$file}}, '';
+ return 1;
+}
+
+=begin _private
+
+=item B<_to_value>
+
+ my $value = _to_value($input);
+
+Converts an C<ok> parameter to its value. Typically this just means
+running it, if it's a code reference. You should run all inputted
+values through this.
+
+=cut
+
+sub _to_value {
+ my ($v) = @_;
+ return ref $v eq 'CODE' ? $v->() : $v;
+}
+
+sub _quote {
+ my $str = $_[0];
+ return "<UNDEF>" unless defined $str;
+ $str =~ s/\\/\\\\/g;
+ $str =~ s/"/\\"/g;
+ $str =~ s/\a/\\a/g;
+ $str =~ s/[\b]/\\b/g;
+ $str =~ s/\e/\\e/g;
+ $str =~ s/\f/\\f/g;
+ $str =~ s/\n/\\n/g;
+ $str =~ s/\r/\\r/g;
+ $str =~ s/\t/\\t/g;
+ if (defined $^V && $^V ge v5.6) {
+ $str =~ s/([[:cntrl:]])(?!\d)/sprintf('\\%o',ord($1))/eg;
+ $str =~ s/([[:^print:]])/sprintf('\\x%02X',ord($1))/eg;
+ $str =~ s/([[:^ascii:]])/sprintf('\\x{%X}',ord($1))/eg;
+ }
+ elsif (ord("A") == 65) {
+ $str =~ s/([\0-\037])(?!\d)/sprintf('\\%o',ord($1))/eg;
+ $str =~ s/([\0-\037\177-\377])/sprintf('\\x%02X',ord($1))/eg;
+ $str =~ s/([^\0-\176])/sprintf('\\x{%X}',ord($1))/eg;
+ }
+ else { # Assuming EBCDIC on this ancient Perl
+
+ # The controls except for one are 0-\077, so almost all controls on
+ # EBCDIC platforms will be expressed in octal, instead of just the C0
+ # ones.
+ $str =~ s/([\0-\077])(?!\d)/sprintf('\\%o',ord($1))/eg;
+ $str =~ s/([\0-\077])/sprintf('\\x%02X',ord($1))/eg;
+
+ $str =~ s/([^\0-\xFF])/sprintf('\\x{%X}',ord($1))/eg;
+
+ # What remains to be escaped are the non-ASCII-range characters,
+ # including the one control that isn't in the 0-077 range.
+ # (We don't escape further any ASCII printables.)
+ $str =~ s<[^ !"\$\%#'()*+,\-./0123456789:;\<=\>?\@ABCDEFGHIJKLMNOPQRSTUVWXYZ\[\\\]^_`abcdefghijklmnopqrstuvwxyz{|}~]><sprintf('\\x%02X',ord($1))>eg;
+ }
+ #if( $_[1] ) {
+ # substr( $str , 218-3 ) = "..."
+ # if length($str) >= 218 and !$ENV{PERL_TEST_NO_TRUNC};
+ #}
+ return qq("$str");
+}
+
+
+=end _private
+
+=item C<ok(...)>
+
+ ok(1 + 1 == 2);
+ ok($have, $expect);
+ ok($have, $expect, $diagnostics);
+
+This function is the reason for C<Test>'s existence. It's
+the basic function that
+handles printing "C<ok>" or "C<not ok>", along with the
+current test number. (That's what C<Test::Harness> wants to see.)
+
+In its most basic usage, C<ok(...)> simply takes a single scalar
+expression. If its value is true, the test passes; if false,
+the test fails. Examples:
+
+ # Examples of ok(scalar)
+
+ ok( 1 + 1 == 2 ); # ok if 1 + 1 == 2
+ ok( $foo =~ /bar/ ); # ok if $foo contains 'bar'
+ ok( baz($x + $y) eq 'Armondo' ); # ok if baz($x + $y) returns
+ # 'Armondo'
+ ok( @a == @b ); # ok if @a and @b are the same
+ # length
+
+The expression is evaluated in scalar context. So the following will
+work:
+
+ ok( @stuff ); # ok if @stuff has any
+ # elements
+ ok( !grep !defined $_, @stuff ); # ok if everything in @stuff
+ # is defined.
+
+A special case is if the expression is a subroutine reference (in either
+C<sub {...}> syntax or C<\&foo> syntax). In
+that case, it is executed and its value (true or false) determines if
+the test passes or fails. For example,
+
+ ok( sub { # See whether sleep works at least passably
+ my $start_time = time;
+ sleep 5;
+ time() - $start_time >= 4
+ });
+
+In its two-argument form, C<ok(I<arg1>, I<arg2>)> compares the two
+scalar values to see if they match. They match if both are undefined,
+or if I<arg2> is a regex that matches I<arg1>, or if they compare equal
+with C<eq>.
+
+ # Example of ok(scalar, scalar)
+
+ ok( "this", "that" ); # not ok, 'this' ne 'that'
+ ok( "", undef ); # not ok, "" is defined
+
+The second argument is considered a regex if it is either a regex
+object or a string that looks like a regex. Regex objects are
+constructed with the qr// operator in recent versions of perl. A
+string is considered to look like a regex if its first and last
+characters are "/", or if the first character is "m"
+and its second and last characters are both the
+same non-alphanumeric non-whitespace character. These regexp
+
+Regex examples:
+
+ ok( 'JaffO', '/Jaff/' ); # ok, 'JaffO' =~ /Jaff/
+ ok( 'JaffO', 'm|Jaff|' ); # ok, 'JaffO' =~ m|Jaff|
+ ok( 'JaffO', qr/Jaff/ ); # ok, 'JaffO' =~ qr/Jaff/;
+ ok( 'JaffO', '/(?i)jaff/ ); # ok, 'JaffO' =~ /jaff/i;
+
+If either (or both!) is a subroutine reference, it is run and used
+as the value for comparing. For example:
+
+ ok sub {
+ open(OUT, '>', 'x.dat') || die $!;
+ print OUT "\x{e000}";
+ close OUT;
+ my $bytecount = -s 'x.dat';
+ unlink 'x.dat' or warn "Can't unlink : $!";
+ return $bytecount;
+ },
+ 4
+ ;
+
+The above test passes two values to C<ok(arg1, arg2)> -- the first
+a coderef, and the second is the number 4. Before C<ok> compares them,
+it calls the coderef, and uses its return value as the real value of
+this parameter. Assuming that C<$bytecount> returns 4, C<ok> ends up
+testing C<4 eq 4>. Since that's true, this test passes.
+
+Finally, you can append an optional third argument, in
+C<ok(I<arg1>,I<arg2>, I<note>)>, where I<note> is a string value that
+will be printed if the test fails. This should be some useful
+information about the test, pertaining to why it failed, and/or
+a description of the test. For example:
+
+ ok( grep($_ eq 'something unique', @stuff), 1,
+ "Something that should be unique isn't!\n".
+ '@stuff = '.join ', ', @stuff
+ );
+
+Unfortunately, a note cannot be used with the single argument
+style of C<ok()>. That is, if you try C<ok(I<arg1>, I<note>)>, then
+C<Test> will interpret this as C<ok(I<arg1>, I<arg2>)>, and probably
+end up testing C<I<arg1> eq I<arg2>> -- and that's not what you want!
+
+All of the above special cases can occasionally cause some
+problems. See L</BUGS and CAVEATS>.
+
+=cut
+
+# A past maintainer of this module said:
+# <<ok(...)'s special handling of subroutine references is an unfortunate
+# "feature" that can't be removed due to compatibility.>>
+#
+
+sub ok ($;$$) {
+ croak "ok: plan before you test!" if !$planned;
+
+ local($\,$,); # guard against -l and other things that screw with
+ # print
+
+ my ($pkg,$file,$line) = caller($TestLevel);
+ my $repetition = ++$history{"$file:$line"};
+ my $context = ("$file at line $line".
+ ($repetition > 1 ? " fail \#$repetition" : ''));
+
+ # Are we comparing two values?
+ my $compare = 0;
+
+ my $ok=0;
+ my $result = _to_value(shift);
+ my ($expected, $isregex, $regex);
+ if (@_ == 0) {
+ $ok = $result;
+ } else {
+ $compare = 1;
+ $expected = _to_value(shift);
+ if (!defined $expected) {
+ $ok = !defined $result;
+ } elsif (!defined $result) {
+ $ok = 0;
+ } elsif (ref($expected) eq 'Regexp') {
+ $ok = $result =~ /$expected/;
+ $regex = $expected;
+ } elsif (($regex) = ($expected =~ m,^ / (.+) / $,sx) or
+ (undef, $regex) = ($expected =~ m,^ m([^\w\s]) (.+) \1 $,sx)) {
+ $ok = $result =~ /$regex/;
+ } else {
+ $ok = $result eq $expected;
+ }
+ }
+ my $todo = $todo{$ntest};
+ if ($todo and $ok) {
+ $context .= ' TODO?!' if $todo;
+ print $TESTOUT "ok $ntest # ($context)\n";
+ } else {
+ # Issuing two seperate prints() causes problems on VMS.
+ if (!$ok) {
+ print $TESTOUT "not ok $ntest\n";
+ }
+ else {
+ print $TESTOUT "ok $ntest\n";
+ }
+
+ $ok or _complain($result, $expected,
+ {
+ 'repetition' => $repetition, 'package' => $pkg,
+ 'result' => $result, 'todo' => $todo,
+ 'file' => $file, 'line' => $line,
+ 'context' => $context, 'compare' => $compare,
+ @_ ? ('diagnostic' => _to_value(shift)) : (),
+ });
+
+ }
+ ++ $ntest;
+ $ok;
+}
+
+
+sub _complain {
+ my($result, $expected, $detail) = @_;
+ $$detail{expected} = $expected if defined $expected;
+
+ # Get the user's diagnostic, protecting against multi-line
+ # diagnostics.
+ my $diag = $$detail{diagnostic};
+ $diag =~ s/\n/\n#/g if defined $diag;
+
+ my $out = $$detail{todo} ? $TESTOUT : $TESTERR;
+ $$detail{context} .= ' *TODO*' if $$detail{todo};
+ if (!$$detail{compare}) {
+ if (!$diag) {
+ print $out "# Failed test $ntest in $$detail{context}\n";
+ } else {
+ print $out "# Failed test $ntest in $$detail{context}: $diag\n";
+ }
+ } else {
+ my $prefix = "Test $ntest";
+
+ print $out "# $prefix got: " . _quote($result) .
+ " ($$detail{context})\n";
+ $prefix = ' ' x (length($prefix) - 5);
+ my $expected_quoted = (defined $$detail{regex})
+ ? 'qr{'.($$detail{regex}).'}' : _quote($expected);
+
+ print $out "# $prefix Expected: $expected_quoted",
+ $diag ? " ($diag)" : (), "\n";
+
+ _diff_complain( $result, $expected, $detail, $prefix )
+ if defined($expected) and 2 < ($expected =~ tr/\n//);
+ }
+
+ if(defined $Program_Lines{ $$detail{file} }[ $$detail{line} ]) {
+ print $out
+ "# $$detail{file} line $$detail{line} is: $Program_Lines{ $$detail{file} }[ $$detail{line} ]\n"
+ if $Program_Lines{ $$detail{file} }[ $$detail{line} ]
+ =~ m/[^\s\#\(\)\{\}\[\]\;]/; # Otherwise it's uninformative
+
+ undef $Program_Lines{ $$detail{file} }[ $$detail{line} ];
+ # So we won't repeat it.
+ }
+
+ push @FAILDETAIL, $detail;
+ return;
+}
+
+
+
+sub _diff_complain {
+ my($result, $expected, $detail, $prefix) = @_;
+ return _diff_complain_external(@_) if $ENV{PERL_TEST_DIFF};
+ return _diff_complain_algdiff(@_)
+ if eval {
+ local @INC = @INC;
+ pop @INC if $INC[-1] eq '.';
+ require Algorithm::Diff; Algorithm::Diff->VERSION(1.15);
+ 1;
+ };
+
+ $told_about_diff++ or print $TESTERR <<"EOT";
+# $prefix (Install the Algorithm::Diff module to have differences in multiline
+# $prefix output explained. You might also set the PERL_TEST_DIFF environment
+# $prefix variable to run a diff program on the output.)
+EOT
+ ;
+ return;
+}
+
+
+
+sub _diff_complain_external {
+ my($result, $expected, $detail, $prefix) = @_;
+ my $diff = $ENV{PERL_TEST_DIFF} || die "WHAAAA?";
+
+ require File::Temp;
+ my($got_fh, $got_filename) = File::Temp::tempfile("test-got-XXXXX");
+ my($exp_fh, $exp_filename) = File::Temp::tempfile("test-exp-XXXXX");
+ unless ($got_fh && $exp_fh) {
+ warn "Can't get tempfiles";
+ return;
+ }
+
+ print $got_fh $result;
+ print $exp_fh $expected;
+ if (close($got_fh) && close($exp_fh)) {
+ my $diff_cmd = "$diff $exp_filename $got_filename";
+ print $TESTERR "#\n# $prefix $diff_cmd\n";
+ if (open(DIFF, '-|', $diff_cmd)) {
+ local $_;
+ while (<DIFF>) {
+ print $TESTERR "# $prefix $_";
+ }
+ close(DIFF);
+ }
+ else {
+ warn "Can't run diff: $!";
+ }
+ } else {
+ warn "Can't write to tempfiles: $!";
+ }
+ unlink($got_filename);
+ unlink($exp_filename);
+ return;
+}
+
+
+
+sub _diff_complain_algdiff {
+ my($result, $expected, $detail, $prefix) = @_;
+
+ my @got = split(/^/, $result);
+ my @exp = split(/^/, $expected);
+
+ my $diff_kind;
+ my @diff_lines;
+
+ my $diff_flush = sub {
+ return unless $diff_kind;
+
+ my $count_lines = @diff_lines;
+ my $s = $count_lines == 1 ? "" : "s";
+ my $first_line = $diff_lines[0][0] + 1;
+
+ print $TESTERR "# $prefix ";
+ if ($diff_kind eq "GOT") {
+ print $TESTERR "Got $count_lines extra line$s at line $first_line:\n";
+ for my $i (@diff_lines) {
+ print $TESTERR "# $prefix + " . _quote($got[$i->[0]]) . "\n";
+ }
+ } elsif ($diff_kind eq "EXP") {
+ if ($count_lines > 1) {
+ my $last_line = $diff_lines[-1][0] + 1;
+ print $TESTERR "Lines $first_line-$last_line are";
+ }
+ else {
+ print $TESTERR "Line $first_line is";
+ }
+ print $TESTERR " missing:\n";
+ for my $i (@diff_lines) {
+ print $TESTERR "# $prefix - " . _quote($exp[$i->[1]]) . "\n";
+ }
+ } elsif ($diff_kind eq "CH") {
+ if ($count_lines > 1) {
+ my $last_line = $diff_lines[-1][0] + 1;
+ print $TESTERR "Lines $first_line-$last_line are";
+ }
+ else {
+ print $TESTERR "Line $first_line is";
+ }
+ print $TESTERR " changed:\n";
+ for my $i (@diff_lines) {
+ print $TESTERR "# $prefix - " . _quote($exp[$i->[1]]) . "\n";
+ print $TESTERR "# $prefix + " . _quote($got[$i->[0]]) . "\n";
+ }
+ }
+
+ # reset
+ $diff_kind = undef;
+ @diff_lines = ();
+ };
+
+ my $diff_collect = sub {
+ my $kind = shift;
+ &$diff_flush() if $diff_kind && $diff_kind ne $kind;
+ $diff_kind = $kind;
+ push(@diff_lines, [@_]);
+ };
+
+
+ Algorithm::Diff::traverse_balanced(
+ \@got, \@exp,
+ {
+ DISCARD_A => sub { &$diff_collect("GOT", @_) },
+ DISCARD_B => sub { &$diff_collect("EXP", @_) },
+ CHANGE => sub { &$diff_collect("CH", @_) },
+ MATCH => sub { &$diff_flush() },
+ },
+ );
+ &$diff_flush();
+
+ return;
+}
+
+
+
+
+#~`~`~`~`~`~`~`~`~`~`~`~`~`~`~`~`~`~`~`~`~`~`~`~`~`~`~`~`~`~`~`~`~`~`~`~`~`~
+
+
+=item C<skip(I<skip_if_true>, I<args...>)>
+
+This is used for tests that under some conditions can be skipped. It's
+basically equivalent to:
+
+ if( $skip_if_true ) {
+ ok(1);
+ } else {
+ ok( args... );
+ }
+
+...except that the C<ok(1)> emits not just "C<ok I<testnum>>" but
+actually "C<ok I<testnum> # I<skip_if_true_value>>".
+
+The arguments after the I<skip_if_true> are what is fed to C<ok(...)> if
+this test isn't skipped.
+
+Example usage:
+
+ my $if_MSWin =
+ $^O =~ m/MSWin/ ? 'Skip if under MSWin' : '';
+
+ # A test to be skipped if under MSWin (i.e., run except under
+ # MSWin)
+ skip($if_MSWin, thing($foo), thing($bar) );
+
+Or, going the other way:
+
+ my $unless_MSWin =
+ $^O =~ m/MSWin/ ? '' : 'Skip unless under MSWin';
+
+ # A test to be skipped unless under MSWin (i.e., run only under
+ # MSWin)
+ skip($unless_MSWin, thing($foo), thing($bar) );
+
+The tricky thing to remember is that the first parameter is true if
+you want to I<skip> the test, not I<run> it; and it also doubles as a
+note about why it's being skipped. So in the first codeblock above, read
+the code as "skip if MSWin -- (otherwise) test whether C<thing($foo)> is
+C<thing($bar)>" or for the second case, "skip unless MSWin...".
+
+Also, when your I<skip_if_reason> string is true, it really should (for
+backwards compatibility with older Test.pm versions) start with the
+string "Skip", as shown in the above examples.
+
+Note that in the above cases, C<thing($foo)> and C<thing($bar)>
+I<are> evaluated -- but as long as the C<skip_if_true> is true,
+then we C<skip(...)> just tosses out their value (i.e., not
+bothering to treat them like values to C<ok(...)>. But if
+you need to I<not> eval the arguments when skipping the
+test, use
+this format:
+
+ skip( $unless_MSWin,
+ sub {
+ # This code returns true if the test passes.
+ # (But it doesn't even get called if the test is skipped.)
+ thing($foo) eq thing($bar)
+ }
+ );
+
+or even this, which is basically equivalent:
+
+ skip( $unless_MSWin,
+ sub { thing($foo) }, sub { thing($bar) }
+ );
+
+That is, both are like this:
+
+ if( $unless_MSWin ) {
+ ok(1); # but it actually appends "# $unless_MSWin"
+ # so that Test::Harness can tell it's a skip
+ } else {
+ # Not skipping, so actually call and evaluate...
+ ok( sub { thing($foo) }, sub { thing($bar) } );
+ }
+
+=cut
+
+sub skip ($;$$$) {
+ local($\, $,); # guard against -l and other things that screw with
+ # print
+
+ my $whyskip = _to_value(shift);
+ if (!@_ or $whyskip) {
+ $whyskip = '' if $whyskip =~ m/^\d+$/;
+ $whyskip =~ s/^[Ss]kip(?:\s+|$)//; # backwards compatibility, old
+ # versions required the reason
+ # to start with 'skip'
+ # We print in one shot for VMSy reasons.
+ my $ok = "ok $ntest # skip";
+ $ok .= " $whyskip" if length $whyskip;
+ $ok .= "\n";
+ print $TESTOUT $ok;
+ ++ $ntest;
+ return 1;
+ } else {
+ # backwards compatibility (I think). skip() used to be
+ # called like ok(), which is weird. I haven't decided what to do with
+ # this yet.
+# warn <<WARN if $^W;
+#This looks like a skip() using the very old interface. Please upgrade to
+#the documented interface as this has been deprecated.
+#WARN
+
+ local($TestLevel) = $TestLevel+1; #to ignore this stack frame
+ return &ok(@_);
+ }
+}
+
+=back
+
+=cut
+
+END {
+ $ONFAIL->(\@FAILDETAIL) if @FAILDETAIL && $ONFAIL;
+}
+
+1;
+__END__
+
+=head1 TEST TYPES
+
+=over 4
+
+=item * NORMAL TESTS
+
+These tests are expected to succeed. Usually, most or all of your tests
+are in this category. If a normal test doesn't succeed, then that
+means that something is I<wrong>.
+
+=item * SKIPPED TESTS
+
+The C<skip(...)> function 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 I<not> available. After the first argument, C<skip(...)> works
+exactly the same way as C<ok(...)> does.
+
+=item * TODO TESTS
+
+TODO tests are designed for maintaining an B<executable TODO list>.
+These tests are I<expected to fail.> If a TODO test does succeed,
+then the feature in question shouldn't 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 in the change log.
+
+=back
+
+=head1 ONFAIL
+
+ BEGIN { plan test => 4, onfail => sub { warn "CALL 911!" } }
+
+Although test failures should be enough, extra diagnostics can be
+triggered at the end of a test run. C<onfail> is passed an array ref
+of hash refs that describe each test failure. Each hash will contain
+at least the following fields: C<package>, C<repetition>, and
+C<result>. (You shouldn't rely on any other fields being present.) If the test
+had an expected value or a diagnostic (or "note") string, these will also be
+included.
+
+The I<optional> C<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 C<onfail> hook from
+running. (It is run inside an C<END> block.) Besides, C<onfail> is
+probably over-kill in most cases. (Your test code should be simpler
+than the code it is testing, yes?)
+
+
+=head1 BUGS and CAVEATS
+
+=over
+
+=item *
+
+C<ok(...)>'s special handing of strings which look like they might be
+regexes can also cause unexpected behavior. An innocent:
+
+ ok( $fileglob, '/path/to/some/*stuff/' );
+
+will fail, since Test.pm considers the second argument to be a regex!
+The best bet is to use the one-argument form:
+
+ ok( $fileglob eq '/path/to/some/*stuff/' );
+
+=item *
+
+C<ok(...)>'s use of string C<eq> can sometimes cause odd problems
+when comparing
+numbers, especially if you're casting a string to a number:
+
+ $foo = "1.0";
+ ok( $foo, 1 ); # not ok, "1.0" ne 1
+
+Your best bet is to use the single argument form:
+
+ ok( $foo == 1 ); # ok "1.0" == 1
+
+=item *
+
+As you may have inferred from the above documentation and examples,
+C<ok>'s prototype is C<($;$$)> (and, incidentally, C<skip>'s is
+C<($;$$$)>). This means, for example, that you can do C<ok @foo, @bar>
+to compare the I<size> of the two arrays. But don't be fooled into
+thinking that C<ok @foo, @bar> means a comparison of the contents of two
+arrays -- you're comparing I<just> the number of elements of each. It's
+so easy to make that mistake in reading C<ok @foo, @bar> that you might
+want to be very explicit about it, and instead write C<ok scalar(@foo),
+scalar(@bar)>.
+
+=item *
+
+This almost definitely doesn't do what you expect:
+
+ ok $thingy->can('some_method');
+
+Why? Because C<can> returns a coderef to mean "yes it can (and the
+method is this...)", and then C<ok> sees a coderef and thinks you're
+passing a function that you want it to call and consider the truth of
+the result of! I.e., just like:
+
+ ok $thingy->can('some_method')->();
+
+What you probably want instead is this:
+
+ ok $thingy->can('some_method') && 1;
+
+If the C<can> returns false, then that is passed to C<ok>. If it
+returns true, then the larger expression S<< C<<
+$thingy->can('some_method') && 1 >> >> returns 1, which C<ok> sees as
+a simple signal of success, as you would expect.
+
+
+=item *
+
+The syntax for C<skip> is about the only way it can be, but it's still
+quite confusing. Just start with the above examples and you'll
+be okay.
+
+Moreover, users may expect this:
+
+ skip $unless_mswin, foo($bar), baz($quux);
+
+to not evaluate C<foo($bar)> and C<baz($quux)> when the test is being
+skipped. But in reality, they I<are> evaluated, but C<skip> just won't
+bother comparing them if C<$unless_mswin> is true.
+
+You could do this:
+
+ skip $unless_mswin, sub{foo($bar)}, sub{baz($quux)};
+
+But that's not terribly pretty. You may find it simpler or clearer in
+the long run to just do things like this:
+
+ if( $^O =~ m/MSWin/ ) {
+ print "# Yay, we're under $^O\n";
+ ok foo($bar), baz($quux);
+ ok thing($whatever), baz($stuff);
+ ok blorp($quux, $whatever);
+ ok foo($barzbarz), thang($quux);
+ } else {
+ print "# Feh, we're under $^O. Watch me skip some tests...\n";
+ for(1 .. 4) { skip "Skip unless under MSWin" }
+ }
+
+But be quite sure that C<ok> is called exactly as many times in the
+first block as C<skip> is called in the second block.
+
+=back
+
+
+=head1 ENVIRONMENT
+
+If C<PERL_TEST_DIFF> environment variable is set, it will be used as a
+command for comparing unexpected multiline results. If you have GNU
+diff installed, you might want to set C<PERL_TEST_DIFF> to C<diff -u>.
+If you don't have a suitable program, you might install the
+C<Text::Diff> module and then set C<PERL_TEST_DIFF> to be C<perl
+-MText::Diff -e 'print diff(@ARGV)'>. If C<PERL_TEST_DIFF> isn't set
+but the C<Algorithm::Diff> module is available, then it will be used
+to show the differences in multiline results.
+
+=for comment
+If C<PERL_TEST_NO_TRUNC> is set, then the initial "Got 'something' but
+expected 'something_else'" readings for long multiline output values aren't
+truncated at about the 230th column, as they normally could be in some
+cases. Normally you won't need to use this, unless you were carefully
+parsing the output of your test programs.
+
+
+=head1 NOTE
+
+A past developer of this module once said that it was no longer being
+actively developed. However, rumors of its demise were greatly
+exaggerated. Feedback and suggestions are quite welcome.
+
+Be aware that the main value of this module is its simplicity. Note
+that there are already more ambitious modules out there, such as
+L<Test::More> and L<Test::Unit>.
+
+Some earlier versions of this module had docs with some confusing
+typos in the description of C<skip(...)>.
+
+
+=head1 SEE ALSO
+
+L<Test::Harness>
+
+L<Test::Simple>, L<Test::More>, L<Devel::Cover>
+
+L<Test::Builder> for building your own testing library.
+
+L<Test::Unit> is an interesting XUnit-style testing library.
+
+L<Test::Inline> lets you embed tests in code.
+
+
+=head1 AUTHOR
+
+Copyright (c) 1998-2000 Joshua Nathaniel Pritikin.
+
+Copyright (c) 2001-2002 Michael G. Schwern.
+
+Copyright (c) 2002-2004 Sean M. Burke.
+
+Current maintainer: Jesse Vincent. E<lt>jesse@bestpractical.comE<gt>
+
+This package is free software and is provided "as is" without express
+or implied warranty. It may be used, redistributed and/or modified
+under the same terms as Perl itself.
+
+=cut
+
+# "Your mistake was a hidden intention."
+# -- /Oblique Strategies/, Brian Eno and Peter Schmidt