+my $d7ff = ucfirst "\x{D7FF}";
+my $d800 = ucfirst "\x{D800}";
+my $dfff = ucfirst "\x{DFFF}";
+my $e000 = ucfirst "\x{E000}";
+my $feff = ucfirst "\x{FEFF}";
+my $fffd = ucfirst "\x{FFFD}";
+my $fffe = ucfirst "\x{FFFE}";
+my $ffff = ucfirst "\x{FFFF}";
+my $hex4 = ucfirst "\x{10000}";
+my $hex5 = ucfirst "\x{100000}";
+my $maxm1 = ucfirst "\x{10FFFE}";
+my $max = ucfirst "\x{10FFFF}";
+my $nonUnicode = ucfirst "\x{110000}";
+EXPECT
+Operation "ucfirst" returns its argument for UTF-16 surrogate U+D800 at - line 3.
+Operation "ucfirst" returns its argument for UTF-16 surrogate U+DFFF at - line 4.
+Operation "ucfirst" returns its argument for non-Unicode code point 0x110000 at - line 14.
+########
+use warnings 'utf8';
+chr(0xD7FF) =~ /\p{Any}/;
+chr(0xD800) =~ /\p{Any}/;
+chr(0xDFFF) =~ /\p{Any}/;
+chr(0xE000) =~ /\p{Any}/;
+chr(0xFEFF) =~ /\p{Any}/;
+chr(0xFFFD) =~ /\p{Any}/;
+chr(0xFFFE) =~ /\p{Any}/;
+chr(0xFFFF) =~ /\p{Any}/;
+chr(0x10000) =~ /\p{Any}/;
+chr(0x100000) =~ /\p{Any}/;
+chr(0x10FFFE) =~ /\p{Any}/;
+chr(0x10FFFF) =~ /\p{Any}/;
+chr(0x110000) =~ /\p{Any}/;
+no warnings 'utf8';
+chr(0xD7FF) =~ /\p{Any}/;
+chr(0xD800) =~ /\p{Any}/;
+chr(0xDFFF) =~ /\p{Any}/;
+chr(0xE000) =~ /\p{Any}/;
+chr(0xFEFF) =~ /\p{Any}/;
+chr(0xFFFD) =~ /\p{Any}/;
+chr(0xFFFE) =~ /\p{Any}/;
+chr(0xFFFF) =~ /\p{Any}/;
+chr(0x10000) =~ /\p{Any}/;
+chr(0x100000) =~ /\p{Any}/;
+chr(0x10FFFE) =~ /\p{Any}/;
+chr(0x10FFFF) =~ /\p{Any}/;
+chr(0x110000) =~ /\p{Any}/;
+EXPECT
+Code point 0x110000 is not Unicode, no properties match it; all inverse properties do at - line 14.
+########
+require "../test.pl";
+use warnings 'utf8';
+my $file = tempfile();
+open(my $fh, "+>:utf8", $file);
+print $fh "\x{D7FF}", "\n";
+print $fh "\x{D800}", "\n";
+print $fh "\x{DFFF}", "\n";
+print $fh "\x{E000}", "\n";
+print $fh "\x{FDCF}", "\n";
+print $fh "\x{FDD0}", "\n";
+print $fh "\x{FDEF}", "\n";
+print $fh "\x{FDF0}", "\n";
+print $fh "\x{FEFF}", "\n";
+print $fh "\x{FFFD}", "\n";
+print $fh "\x{FFFE}", "\n";
+print $fh "\x{FFFF}", "\n";
+print $fh "\x{10000}", "\n";
+print $fh "\x{1FFFE}", "\n";
+print $fh "\x{1FFFF}", "\n";
+print $fh "\x{2FFFE}", "\n";
+print $fh "\x{2FFFF}", "\n";
+print $fh "\x{3FFFE}", "\n";
+print $fh "\x{3FFFF}", "\n";
+print $fh "\x{4FFFE}", "\n";
+print $fh "\x{4FFFF}", "\n";
+print $fh "\x{5FFFE}", "\n";
+print $fh "\x{5FFFF}", "\n";
+print $fh "\x{6FFFE}", "\n";
+print $fh "\x{6FFFF}", "\n";
+print $fh "\x{7FFFE}", "\n";
+print $fh "\x{7FFFF}", "\n";
+print $fh "\x{8FFFE}", "\n";
+print $fh "\x{8FFFF}", "\n";
+print $fh "\x{9FFFE}", "\n";
+print $fh "\x{9FFFF}", "\n";
+print $fh "\x{AFFFE}", "\n";
+print $fh "\x{AFFFF}", "\n";
+print $fh "\x{BFFFE}", "\n";
+print $fh "\x{BFFFF}", "\n";
+print $fh "\x{CFFFE}", "\n";
+print $fh "\x{CFFFF}", "\n";
+print $fh "\x{DFFFE}", "\n";
+print $fh "\x{DFFFF}", "\n";
+print $fh "\x{EFFFE}", "\n";
+print $fh "\x{EFFFF}", "\n";
+print $fh "\x{FFFFE}", "\n";
+print $fh "\x{FFFFF}", "\n";
+print $fh "\x{100000}", "\n";
+print $fh "\x{10FFFE}", "\n";
+print $fh "\x{10FFFF}", "\n";
+print $fh "\x{110000}", "\n";
+close $fh;
+EXPECT
+Unicode surrogate U+D800 is illegal in UTF-8 at - line 6.
+Unicode surrogate U+DFFF is illegal in UTF-8 at - line 7.
+Unicode non-character U+FDD0 is illegal for open interchange at - line 10.
+Unicode non-character U+FDEF is illegal for open interchange at - line 11.
+Unicode non-character U+FFFE is illegal for open interchange at - line 15.
+Unicode non-character U+FFFF is illegal for open interchange at - line 16.
+Unicode non-character U+1FFFE is illegal for open interchange at - line 18.
+Unicode non-character U+1FFFF is illegal for open interchange at - line 19.
+Unicode non-character U+2FFFE is illegal for open interchange at - line 20.
+Unicode non-character U+2FFFF is illegal for open interchange at - line 21.
+Unicode non-character U+3FFFE is illegal for open interchange at - line 22.
+Unicode non-character U+3FFFF is illegal for open interchange at - line 23.
+Unicode non-character U+4FFFE is illegal for open interchange at - line 24.
+Unicode non-character U+4FFFF is illegal for open interchange at - line 25.
+Unicode non-character U+5FFFE is illegal for open interchange at - line 26.
+Unicode non-character U+5FFFF is illegal for open interchange at - line 27.
+Unicode non-character U+6FFFE is illegal for open interchange at - line 28.
+Unicode non-character U+6FFFF is illegal for open interchange at - line 29.
+Unicode non-character U+7FFFE is illegal for open interchange at - line 30.
+Unicode non-character U+7FFFF is illegal for open interchange at - line 31.
+Unicode non-character U+8FFFE is illegal for open interchange at - line 32.
+Unicode non-character U+8FFFF is illegal for open interchange at - line 33.
+Unicode non-character U+9FFFE is illegal for open interchange at - line 34.
+Unicode non-character U+9FFFF is illegal for open interchange at - line 35.
+Unicode non-character U+AFFFE is illegal for open interchange at - line 36.
+Unicode non-character U+AFFFF is illegal for open interchange at - line 37.
+Unicode non-character U+BFFFE is illegal for open interchange at - line 38.
+Unicode non-character U+BFFFF is illegal for open interchange at - line 39.
+Unicode non-character U+CFFFE is illegal for open interchange at - line 40.
+Unicode non-character U+CFFFF is illegal for open interchange at - line 41.
+Unicode non-character U+DFFFE is illegal for open interchange at - line 42.
+Unicode non-character U+DFFFF is illegal for open interchange at - line 43.
+Unicode non-character U+EFFFE is illegal for open interchange at - line 44.
+Unicode non-character U+EFFFF is illegal for open interchange at - line 45.
+Unicode non-character U+FFFFE is illegal for open interchange at - line 46.
+Unicode non-character U+FFFFF is illegal for open interchange at - line 47.
+Unicode non-character U+10FFFE is illegal for open interchange at - line 49.
+Unicode non-character U+10FFFF is illegal for open interchange at - line 50.
+Code point 0x110000 is not Unicode, may not be portable at - line 51.
+########
+require "../test.pl";
+no warnings 'utf8';
+my $file = tempfile();
+open(my $fh, "+>:utf8", $file);
+print $fh "\x{D7FF}", "\n";
+print $fh "\x{D800}", "\n";
+print $fh "\x{DFFF}", "\n";
+print $fh "\x{E000}", "\n";
+print $fh "\x{FDCF}", "\n";
+print $fh "\x{FDD0}", "\n";
+print $fh "\x{FDEF}", "\n";
+print $fh "\x{FDF0}", "\n";
+print $fh "\x{FEFF}", "\n";
+print $fh "\x{FFFD}", "\n";
+print $fh "\x{FFFE}", "\n";
+print $fh "\x{FFFF}", "\n";
+print $fh "\x{10000}", "\n";
+print $fh "\x{1FFFE}", "\n";
+print $fh "\x{1FFFF}", "\n";
+print $fh "\x{2FFFE}", "\n";
+print $fh "\x{2FFFF}", "\n";
+print $fh "\x{3FFFE}", "\n";
+print $fh "\x{3FFFF}", "\n";
+print $fh "\x{4FFFE}", "\n";
+print $fh "\x{4FFFF}", "\n";
+print $fh "\x{5FFFE}", "\n";
+print $fh "\x{5FFFF}", "\n";
+print $fh "\x{6FFFE}", "\n";
+print $fh "\x{6FFFF}", "\n";
+print $fh "\x{7FFFE}", "\n";
+print $fh "\x{7FFFF}", "\n";
+print $fh "\x{8FFFE}", "\n";
+print $fh "\x{8FFFF}", "\n";
+print $fh "\x{9FFFE}", "\n";
+print $fh "\x{9FFFF}", "\n";
+print $fh "\x{AFFFE}", "\n";
+print $fh "\x{AFFFF}", "\n";
+print $fh "\x{BFFFE}", "\n";
+print $fh "\x{BFFFF}", "\n";
+print $fh "\x{CFFFE}", "\n";
+print $fh "\x{CFFFF}", "\n";
+print $fh "\x{DFFFE}", "\n";
+print $fh "\x{DFFFF}", "\n";
+print $fh "\x{EFFFE}", "\n";
+print $fh "\x{EFFFF}", "\n";
+print $fh "\x{FFFFE}", "\n";
+print $fh "\x{FFFFF}", "\n";
+print $fh "\x{100000}", "\n";
+print $fh "\x{10FFFE}", "\n";
+print $fh "\x{10FFFF}", "\n";
+print $fh "\x{110000}", "\n";
+close $fh;