Yes, but that's not what the question was. It was asked whether there is any value of $x for which test($x) with the given code (i.e. decode('iso-8859-1',...)) returns 0.  By modifying the code you can of course achieve anything...  But this is kind of like

"Is there any case in which this code will return 0?"

sub test {
    if (1) {
        return 1;
    } else {
        retrun 0;
    }
}
[download]

Yes, there is:

sub test {
    if (0) {
        return 1;
    } else {
        retrun 0;
    }
}
[download]