+#!./perl
+#
+# check UNIVERSAL
+#
+
+BEGIN {
+ chdir 't' if -d 't';
+ unshift @INC, '../lib' if -d '../lib';
+ $| = 1;
+}
+
+print "1..80\n";
+
+$a = {};
+bless $a, "Bob";
+print "not " unless $a->isa("Bob");
+print "ok 1\n";
+
+package Human;
+sub eat {}
+
+package Female;
+@ISA=qw(Human);
+
+package Alice;
+@ISA=qw(Bob Female);
+sub drink {}
+sub new { bless {} }
+
+$Alice::VERSION = 2.718;
+
+{
+ package Cedric;
+ our @ISA;
+ use base qw(Human);
+}
+
+{
+ package Programmer;
+ our $VERSION = 1.667;
+
+ sub write_perl { 1 }
+}
+
+package main;
+
+my $i = 2;
+sub test { print "not " unless shift; print "ok $i\n"; $i++; }
+
+$a = new Alice;
+
+test $a->isa("Alice");
+
+test $a->isa("Bob");
+
+test $a->isa("Female");
+
+test $a->isa("Human");
+
+test ! $a->isa("Male");
+
+test ! $a->isa('Programmer');
+
+test $a->can("drink");
+
+test $a->can("eat");
+
+test ! $a->can("sleep");
+
+test (!Cedric->isa('Programmer'));
+
+test (Cedric->isa('Human'));
+
+push(@Cedric::ISA,'Programmer');
+
+test (Cedric->isa('Programmer'));
+
+{
+ package Alice;
+ base::->import('Programmer');
+}
+
+test $a->isa('Programmer');
+test $a->isa("Female");
+
+@Cedric::ISA = qw(Bob);
+
+test (!Cedric->isa('Programmer'));
+
+my $b = 'abc';
+my @refs = qw(SCALAR SCALAR LVALUE GLOB ARRAY HASH CODE);
+my @vals = ( \$b, \3.14, \substr($b,1,1), \*b, [], {}, sub {} );
+for ($p=0; $p < @refs; $p++) {
+ for ($q=0; $q < @vals; $q++) {
+ test UNIVERSAL::isa($vals[$p], $refs[$q]) eq ($p==$q or $p+$q==1);
+ };
+};
+
+test ! UNIVERSAL::can(23, "can");
+
+test $a->can("VERSION");
+
+test $a->can("can");
+test ! $a->can("export_tags"); # a method in Exporter
+
+test (eval { $a->VERSION }) == 2.718;
+
+test ! (eval { $a->VERSION(2.719) }) &&
+ $@ =~ /^Alice version 2.71(?:9|8999\d+) required--this is only version 2.718 at /;
+
+test (eval { $a->VERSION(2.718) }) && ! $@;
+
+my $subs = join ' ', sort grep { defined &{"UNIVERSAL::$_"} } keys %UNIVERSAL::;
+if ('a' lt 'A') {
+ test $subs eq "can isa VERSION";
+} else {
+ test $subs eq "VERSION can isa";
+}
+
+test $a->isa("UNIVERSAL");
+
+# now use UNIVERSAL.pm and see what changes
+eval "use UNIVERSAL";
+
+test $a->isa("UNIVERSAL");
+
+my $sub2 = join ' ', sort grep { defined &{"UNIVERSAL::$_"} } keys %UNIVERSAL::;
+# XXX import being here is really a bug
+if ('a' lt 'A') {
+ test $sub2 eq "can import isa VERSION";
+} else {
+ test $sub2 eq "VERSION can import isa";
+}
+
+eval 'sub UNIVERSAL::sleep {}';
+test $a->can("sleep");
+
+test ! UNIVERSAL::can($b, "can");
+
+test ! $a->can("export_tags"); # a method in Exporter
+
+test ! UNIVERSAL::isa("\xff\xff\xff\0", 'HASH');