#!./perl BEGIN { unless (-d 'blib') { chdir 't' if -d 't'; } require q(./test.pl); set_up_inc('../lib'); } use strict; use warnings; plan(tests => 1); require mro; =pod This example is take from: http://www.python.org/2.3/mro.html "Serious order disagreement" # From Guido class O: pass class X(O): pass class Y(O): pass class A(X,Y): pass class B(Y,X): pass try: class Z(A,B): pass #creates Z(A,B) in Python 2.2 except TypeError: pass # Z(A,B) cannot be created in Python 2.3 =cut { package X; package Y; package XY; our @ISA = ('X', 'Y'); package YX; our @ISA = ('Y', 'X'); package Z; our @ISA = ('XY', 'YX'); } eval { mro::get_linear_isa('Z', 'c3') }; like($@, qr/^Inconsistent hierarchy during C3 merge of class 'Z'/, '... got the right error with an inconsistent hierarchy');