$req->args_status(1); # set error state for query-string parser
ok $req->param_status == 1;
 
$foo = $req->param("foo");
ok $foo == 1;
eval { @foo = $req->param("foo") };
ok $@->isa("Apache2::Request::Error");
undef $@;
eval { my $not_found = $req->param("non-existent-param") };
ok $@->isa("Apache2::Request::Error");
 
$req->args_status(0); # reset query-string parser state to "success"