In addition, you could post some of your Test::MockObject or Test::MockModule code, and possibly someone could help you with getting it to work.

============== Foo.pm ==============
package Foo;

use strict;
require Exporter;

our @ISA = qw(Exporter);
our %EXPORT_TAGS = ( 'all' => [ qw(
   foo
) ] );

our @EXPORT_OK = ( @{ $EXPORT_TAGS{'all'} } );

our $VERSION = '0.01';

sub foo
{
   die "This is being called from Foo\n";
}
1;
__END__
============== Bar.pm ==============
package Bar;

use strict;
use Foo qw(foo);
our $VERSION = '0.01';

sub new
{
   my ($class) = @_;
   my $self = [];
   bless($self, $class);
}

sub bar
{
   my ($self) = shift;
   foo();
}

1;
__END__
============== Baz.pl ==============
use strict;
use warnings;

use Test::MockModule;
use Bar;

{
   my $mock = Test::MockModule->new('Foo');
   $mock->mock('foo', sub {print "Successfully mocked!\n";});
   my $bar = Bar->new();
   $bar->bar();
}
[download]

thor

Your problem here is that your Foo module has already exported &foo into Bar's namespace by the time you have mocked anything. What you want to do is to mock Foo before loading Bar, like this:

use strict;
use warnings;

use Test::MockModule;

my $mock = Test::MockModule->new('Foo');
$mock->mock('foo', sub {print "Successfully mocked!\n";});

require Bar;
my $bar = Bar->new();
$bar->bar();
[download]

Personally I don't think this is ideal since you need to require Bar rather than use it.

However, since you are exporting &Foo::foo into Bar, you could ignore the fact &Foo::foo came from Foo, and just mock &foo inside Bar. Like this:

use strict;
use warnings;

use Test::MockModule;
use Bar;

my $mock = Test::MockModule->new('Bar');
$mock->mock('foo', sub {print "Successfully mocked!\n";});
     
my $bar = Bar->new();
$bar->bar();
[download]

This too is probably not ideal.

Of course, if you simply do not export &Foo::foo, and instead call with the fully qualitied packag name (Foo::foo()) then you original test code will work.

-stvn