use warnings;
use strict;

use Mock::Sub;

my $m = Mock::Sub->new;

sub foo ($$$){
    return undef;
}

my $foo_sub = $m->mock('foo');

##</code><code>##

Prototype mismatch: sub main::foo ($$$) vs none at /home/stevieb/perl5/perlbrew/perls/perl-5.26.1/lib/site_perl/5.26.1/Mock/Sub/Child.pm line 122.
Prototype mismatch: sub main::foo: none vs ($$$) at /home/stevieb/perl5/perlbrew/perls/perl-5.26.1/lib/site_perl/5.26.1/Mock/Sub/Child.pm line 140.

##</code><code>##

use warnings;
use strict;
use feature 'say';

use Mock::Sub;

$SIG{__WARN__} = sub {say $_[0] if $_[0] !~ /Prototype/};

my $m = Mock::Sub->new;

sub foo ($$$){
    say "hello!"; # doesn't get called
    return undef;
}

my $foo = $m->mock('foo');
$foo->return_value('test');

say foo(1, 2, 3);
say foo(1, 2, 3);
say foo(1, 2, 3);

say $foo->called_count;

##</code><code>##

test
test
test
3

##</code><code>##

Not enough arguments for main::foo at mock.pl line 21, near "()"
Execution of mock.pl aborted due to compilation errors.

##</code><code>##

    {
        no strict 'refs';
        no warnings 'redefine';
 
        my $mock = $self;
        weaken $mock;
 
        *$sub = sub {
 
            @{ $mock->{called_with} } = @_;
            ++$mock->{called_count};
 
            if ($mock->{side_effect}) {
                if (wantarray){
                    my @effect = $mock->{side_effect}->(@_);
                    return @effect if @effect;
                }
                else {
                    my $effect = $mock->{side_effect}->(@_);
                    return $effect if defined $effect;
                }
            }
 
            return if ! defined $mock->{return};
 
            if ($mock->{return}[0] && $mock->{return}[0] eq 'params'){
                return ! wantarray ? $_[0] : @_;
            }
            else {
                return ! wantarray && @{ $mock->{return} } == 1
                    ? $mock->{return}[0]
                    : @{ $mock->{return} };
            }
        };
    }