package Love; sub new { return bless {}, Love; } sub marry { my $self = shift; my $user1 = shift; my $user2 = shift; my $db_object = $self->{'db_object'}; if ( $db_object->is_married($user1) == 0 && $db_object->is_married($user2) == 0 ) { $db_object->marry( $user1, $user2 ); $db_object->marry( $user2, $user1 ); return 1; } return 0; } package MyDbClass; sub is_married { # do some complicated stuff } sub marry { # do some other complicated stuff } #Our test can be use Test::Pockito; use Test::Simple; my $pocket = Test::Pockito->new("MyNamespace"); my $db_mock = $pocket->mock("MyDbClass"); $pocket->when( $db_mock->is_married("bob") )->then(0); $pocket->when( $db_mock->is_married("alice") )->then(0); $pocket->when( $db_mock->marry( "alice", "bob" ) )->then(); $pocket->when( $db_mock->marry( "bob", "alice" ) )->then(); my $target = Love->new(); $target->{'db_object'} = $db_mock; ok( $target->marry( "bob", "alice" ) == 1, "single to married == success!" ); ok( scalar keys %{ $pocket->expected_calls } == 0, "No extra cruft calls, huzzah!" );