#!perl -T use 5.010; use strict; use warnings; ## My::Module - Module I'm writing unit tests for package My::Module; use Carp; use IO::Socket 1.18; sub new { my $class = shift; bless { }, $class } sub connect { my $s = shift; $s->{socket} = IO::Socket::INET->new( PeerAddr => '127.0.0.1', PeerPort => 8080, Proto => 'tcp', ) or croak "Connection failed: $!"; croak 'Invalid handshake' unless $s->{socket}->recv eq 'Hiya!'; $s->{socket}->send('Howdy!'); croak 'ACK barf' unless $s->{socket}->recv eq 'Welcome'; 1; } ## main - Reasonable facsimile for t/02-connect.t package main; use Test::More; use Test::MockModule; my $obj = mock_me( send => sub { $_[0]->{howdy} = 1 if $_[1] eq 'Howdy!' }, recv => sub { $_[0]->{howdy} ? 'Welcome' : 'Hiya!' }, ); is 'My::Module', ref $obj, 'Correct module'; lives_ok { $obj->connect } 'Connection and handshake success'; done_testing; # Mock for IO::Socket::INET with the provided overrides sub mock_me { my $mock = Test::MockModule->new('IO::Socket::INET'); my %mock = ( new => sub { $mock }, send => sub { warn "send($_[0])" }, recv => sub { warn "recv" }, @_ ); $mock->mock($_ => $mock{$_}) for keys %mock; My::Module->new; } __END__ ok 1 - Correct module Can't locate object method "recv" via package "Test::MockModule" at test.pl line 24. # Tests were run but no plan was declared and done_testing() was not seen. # Looks like your test exited with 255 just after 1.