use Scalar::Vec::Util;
-eval { Scalar::Vec::Util::vfill_pp(undef, 0, 0, 0) };
-like($@, qr/Invalid\s+argument/, 'first argument undef croaks');
-eval { Scalar::Vec::Util::vfill_pp(my $x, undef, 0, 0) };
-like($@, qr/Invalid\s+argument/, 'second argument undef croaks');
-eval { Scalar::Vec::Util::vfill_pp(my $x, 0, undef, 0) };
-like($@, qr/Invalid\s+argument/, 'third argument undef croaks');
-eval { Scalar::Vec::Util::vfill_pp(my $x, 0, 0, undef) };
-like($@, qr/Invalid\s+argument/, 'fourth argument undef croaks');
+BEGIN {
+ *myeq = *Scalar::Vec::Util::veq_pp;
+}
+
+for ([ 1, 'offset', -1 ], [ 2, 'length', '-1' ]) {
+ my @args = ('1') x 4;
+ $args[$_->[0]] = $_->[2];
+ local $@;
+ eval { &Scalar::Vec::Util::vfill_pp(@args) };
+ my $err = $@;
+ my $line = __LINE__-2;
+ like $err, qr/^Invalid\s+negative\s+$_->[1]\s+at\s+\Q$0\E\s+line\s+$line/,
+ "vfill_pp(@args) failed";
+}
+
+my $p = 8;
+my $n = 3 * $p;
+my $q = 1;
+
+sub myfill {
+ my (undef, $s, $l, $x) = @_;
+ $x = 1 if $x;
+ vec($_[0], $_, 1) = $x for $s .. $s + $l - 1;
+}
+
+sub rst {
+ myfill $_[0], 0, $n, 0;
+ $_[0] = '';
+}
+
+my ($v, $c) = ('') x 2;
+
+my @s = ($p - $q) .. ($p + $q);
+for my $s (@s) {
+ for my $l (0 .. $n - 1) {
+ next if $s + $l > $n;
+ my $desc = "vfill_pp $s, $l";
+ rst $c;
+ myfill $c, 0, $s, 0;
+ myfill $c, $s, $l, 1;
+ rst $v;
+ Scalar::Vec::Util::vfill_pp($v, 0, $s, 0);
+ Scalar::Vec::Util::vfill_pp($v, $s, $l, 1);
+ is length $v, length $c, "$desc: length";
+ ok myeq($v, 0, $c, 0, $n), "$desc: bits";
+ }
+}