You can force print to fail by
selecting a filehandle that you know is unwritable. Here's a quick-n-dirty little module that returns a tied filehandle that fails when written to:
package NoPrint;
use Symbol;
sub new {
my $sym = gensym;
tie *$sym, $_[0];
bless $sym, $_[0];
}
sub TIEHANDLE { bless {}, $_[0] }
sub PRINT { return undef }
sub PRINTF { return undef }
sub WRITE { return undef }
You can now use it like this:
my $old_fh = select NoPrint->new;
## deep inside some test somewhere...
print "foo\n" or warn "print failed (1)";
select $old_fh;
## now printing is back to normal again:
print "foo\n" or warn "print failed (2)";
Update:
An alternative that
might even be is much cleaner is to localize *STDOUT:
{
local *STDOUT = NoPrint->new;
print "foo\n" or warn "print failed (1)";
}
print "foo\n" or warn "print failed (2)";