Add query string encoding & decoding functions

t/fcgi.t

@@ -13,7 +13,7 @@ sub start {
 sub record($id, $type, $data, $pad=undef) {
     $pad //= rand > 0.5 ? int rand(50) : 0;
     my $msg = pack('CCnnCC', 1, $type, $id, length($data), $pad, 0) . $data . ("\0"x$pad);
-    is $remote->syswrite($msg, length($msg)), length($msg);
+    die "Short write" if $remote->syswrite($msg, length($msg)) != length($msg);
 }
 
 sub begin($id=1, $role=1, $keep=0) {

t/query.t

@@ -0,0 +1,27 @@
+use v5.36;
+use Test::More;
+use FU::Util qw/query_decode query_encode/;
+use experimental 'builtin';
+
+is_deeply
+    query_decode('a&a&%c3%be=%26%3d%c3%be&a=3'),
+    { a => [ builtin::true, builtin::true, 3 ], "\xfe" => "&=\xfe" };
+
+ok !eval { query_decode('%10'); 1 };
+like $@, qr/Invalid control character/;
+
+is query_encode
+    { a => builtin::true, b => undef, c => builtin::false, d => 'string', e => "&=\xfe" },
+    'a&d=string&e=%26%3d%c3%be';
+
+is query_encode
+    { "\xfe" => [ 1, undef, 3, builtin::false, builtin::true ] },
+    "%c3%be=1&%c3%be=3&%c3%be";
+
+sub FUTILTEST::TO_QUERY { '&'.($_[0][0] + 1) }
+
+is query_encode
+    { -ab => bless [2], 'FUTILTEST' },
+    '-ab=%263';
+
+done_testing;