my $LOG_ERROR;                                                                                         
my $_log_error_sub_cache;
sub setup
{
    my $class = shift;
    $class->SUPER::setup_test;
    $_log_error_sub_cache = *RTK::Digitrak::LogRun::_log_error{CODE};
    no warnings 'redefine';
    *Foo::Bar_log_error = sub($) { $LOG_ERROR = shift };
}                                                                                                 

sub teardown
{
    my $class = shift;
    $class->SUPER::teardown_test;
    no warnings 'redefine';
    *Foo::Bar:_log_error = $_log_error_sub_cache;
}