X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=t%2Fop%2Fsubstr.t;h=85574d56ec9f4942f4a7faab50f305d184fb12de;hb=a4c04bdcc508b6a45f83e703d0f82401445aa55b;hp=25336365b9a6fa8d2fa17240d6d775976b0f13a2;hpb=79072805bf63abe5b5978b5928ab00d360ea3e7f;p=p5sagit%2Fp5-mst-13.2.git

diff --git a/t/op/substr.t b/t/op/substr.t
index 2533636..85574d5 100755
--- a/t/op/substr.t
+++ b/t/op/substr.t
@@ -1,47 +1,587 @@
 #!./perl
 
-# $RCSfile: substr.t,v $$Revision: 4.1 $$Date: 92/08/07 18:28:31 $
+print "1..174\n";
 
-print "1..22\n";
+#P = start of string  Q = start of substr  R = end of substr  S = end of string
+
+BEGIN {
+    chdir 't' if -d 't';
+    @INC = '../lib';
+}
+use warnings ;
 
 $a = 'abcdefxyz';
+$SIG{__WARN__} = sub {
+     if ($_[0] =~ /^substr outside of string/) {
+          $w++;
+     } elsif ($_[0] =~ /^Attempt to use reference as lvalue in substr/) {
+          $w += 2;
+     } elsif ($_[0] =~ /^Use of uninitialized value/) {
+          $w += 3;
+     } else {
+          warn $_[0];
+     }
+};
+
+sub ok { print (($_[1] ? "" : "not ") . "ok $_[0]\n") }
+
+$FATAL_MSG = '^substr outside of string' ;
 
-print (substr($a,0,3) eq 'abc' ? "ok 1\n" : "not ok 1\n");
-print (substr($a,3,3) eq 'def' ? "ok 2\n" : "not ok 2\n");
-print (substr($a,6,999) eq 'xyz' ? "ok 3\n" : "not ok 3\n");
-print (substr($a,999,999) eq '' ? "ok 4\n" : "not ok 4\n");
-print (substr($a,6,-1) eq '' ? "ok 5\n" : "not ok 5\n");
-print (substr($a,-3,1) eq 'x' ? "ok 6\n" : "not ok 6\n");
+ok 1, substr($a,0,3) eq 'abc';   # P=Q R S
+ok 2, substr($a,3,3) eq 'def';   # P Q R S
+ok 3, substr($a,6,999) eq 'xyz'; # P Q S R
+$b = substr($a,999,999) ; # warn # P R Q S
+ok 4, $w-- == 1 ;
+eval{substr($a,999,999) = "" ; };# P R Q S
+ok 5, $@ =~ /$FATAL_MSG/;
+ok 6, substr($a,0,-6) eq 'abc';  # P=Q R S
+ok 7, substr($a,-3,1) eq 'x';    # P Q R S
 
 $[ = 1;
 
-print (substr($a,1,3) eq 'abc' ? "ok 7\n" : "not ok 7\n");
-print (substr($a,4,3) eq 'def' ? "ok 8\n" : "not ok 8\n");
-print (substr($a,7,999) eq 'xyz' ? "ok 9\n" : "not ok 9\n");
-print (substr($a,999,999) eq '' ? "ok 10\n" : "not ok 10\n");
-print (substr($a,7,-1) eq '' ? "ok 11\n" : "not ok 11\n");
-print (substr($a,-3,1) eq 'x' ? "ok 12\n" : "not ok 12\n");
+ok 8, substr($a,1,3) eq 'abc' ;  # P=Q R S
+ok 9, substr($a,4,3) eq 'def' ;  # P Q R S
+ok 10, substr($a,7,999) eq 'xyz';# P Q S R
+$b = substr($a,999,999) ; # warn # P R Q S
+ok 11, $w-- == 1 ;
+eval{substr($a,999,999) = "" ; } ; # P R Q S
+ok 12, $@ =~ /$FATAL_MSG/;
+ok 13, substr($a,1,-6) eq 'abc' ;# P=Q R S
+ok 14, substr($a,-3,1) eq 'x' ;  # P Q R S
 
 $[ = 0;
 
 substr($a,3,3) = 'XYZ';
-print $a eq 'abcXYZxyz' ? "ok 13\n" : "not ok 13\n";
+ok 15, $a eq 'abcXYZxyz' ;
 substr($a,0,2) = '';
-print $a eq 'cXYZxyz' ? "ok 14\n" : "not ok 14\n";
-y/a/a/;
+ok 16, $a eq 'cXYZxyz' ;
 substr($a,0,0) = 'ab';
-print $a eq 'abcXYZxyz' ? "ok 15\n" : "not ok 15 $a\n";
+ok 17, $a eq 'abcXYZxyz' ;
 substr($a,0,0) = '12345678';
-print $a eq '12345678abcXYZxyz' ? "ok 16\n" : "not ok 16\n";
+ok 18, $a eq '12345678abcXYZxyz' ;
 substr($a,-3,3) = 'def';
-print $a eq '12345678abcXYZdef' ? "ok 17\n" : "not ok 17\n";
+ok 19, $a eq '12345678abcXYZdef';
 substr($a,-3,3) = '<';
-print $a eq '12345678abcXYZ<' ? "ok 18\n" : "not ok 18\n";
+ok 20, $a eq '12345678abcXYZ<' ;
 substr($a,-1,1) = '12345678';
-print $a eq '12345678abcXYZ12345678' ? "ok 19\n" : "not ok 19\n";
+ok 21, $a eq '12345678abcXYZ12345678' ;
 
 $a = 'abcdefxyz';
 
-print (substr($a,6) eq 'xyz' ? "ok 20\n" : "not ok 20\n");
-print (substr($a,-3) eq 'xyz' ? "ok 21\n" : "not ok 21\n");
-print (substr($a,999) eq '' ? "ok 22\n" : "not ok 22\n");
+ok 22, substr($a,6) eq 'xyz' ;        # P Q R=S
+ok 23, substr($a,-3) eq 'xyz' ;       # P Q R=S
+$b = substr($a,999,999) ; # warning   # P R=S Q
+ok 24, $w-- == 1 ;
+eval{substr($a,999,999) = "" ; } ;    # P R=S Q
+ok 25, $@ =~ /$FATAL_MSG/;
+ok 26, substr($a,0) eq 'abcdefxyz' ;  # P=Q R=S
+ok 27, substr($a,9) eq '' ;           # P Q=R=S
+ok 28, substr($a,-11) eq 'abcdefxyz'; # Q P R=S
+ok 29, substr($a,-9) eq 'abcdefxyz';  # P=Q R=S
+
+$a = '54321';
+
+$b = substr($a,-7, 1) ; # warn  # Q R P S
+ok 30, $w-- == 1 ;
+eval{substr($a,-7, 1) = "" ; }; # Q R P S
+ok 31, $@ =~ /$FATAL_MSG/;
+$b = substr($a,-7,-6) ; # warn  # Q R P S
+ok 32, $w-- == 1 ;
+eval{substr($a,-7,-6) = "" ; }; # Q R P S
+ok 33, $@ =~ /$FATAL_MSG/;
+ok 34, substr($a,-5,-7) eq '';  # R P=Q S
+ok 35, substr($a, 2,-7) eq '';  # R P Q S
+ok 36, substr($a,-3,-7) eq '';  # R P Q S
+ok 37, substr($a, 2,-5) eq '';  # P=R Q S
+ok 38, substr($a,-3,-5) eq '';  # P=R Q S
+ok 39, substr($a, 2,-4) eq '';  # P R Q S
+ok 40, substr($a,-3,-4) eq '';  # P R Q S
+ok 41, substr($a, 5,-6) eq '';  # R P Q=S
+ok 42, substr($a, 5,-5) eq '';  # P=R Q S
+ok 43, substr($a, 5,-3) eq '';  # P R Q=S
+$b = substr($a, 7,-7) ; # warn  # R P S Q
+ok 44, $w-- == 1 ;
+eval{substr($a, 7,-7) = "" ; }; # R P S Q
+ok 45, $@ =~ /$FATAL_MSG/;
+$b = substr($a, 7,-5) ; # warn  # P=R S Q
+ok 46, $w-- == 1 ;
+eval{substr($a, 7,-5) = "" ; }; # P=R S Q
+ok 47, $@ =~ /$FATAL_MSG/;
+$b = substr($a, 7,-3) ; # warn  # P Q S Q
+ok 48, $w-- == 1 ;
+eval{substr($a, 7,-3) = "" ; }; # P Q S Q
+ok 49, $@ =~ /$FATAL_MSG/;
+$b = substr($a, 7, 0) ; # warn  # P S Q=R
+ok 50, $w-- == 1 ;
+eval{substr($a, 7, 0) = "" ; }; # P S Q=R
+ok 51, $@ =~ /$FATAL_MSG/;
+
+ok 52, substr($a,-7,2) eq '';   # Q P=R S
+ok 53, substr($a,-7,4) eq '54'; # Q P R S
+ok 54, substr($a,-7,7) eq '54321';# Q P R=S
+ok 55, substr($a,-7,9) eq '54321';# Q P S R
+ok 56, substr($a,-5,0) eq '';   # P=Q=R S
+ok 57, substr($a,-5,3) eq '543';# P=Q R S
+ok 58, substr($a,-5,5) eq '54321';# P=Q R=S
+ok 59, substr($a,-5,7) eq '54321';# P=Q S R
+ok 60, substr($a,-3,0) eq '';   # P Q=R S
+ok 61, substr($a,-3,3) eq '321';# P Q R=S
+ok 62, substr($a,-2,3) eq '21'; # P Q S R
+ok 63, substr($a,0,-5) eq '';   # P=Q=R S
+ok 64, substr($a,2,-3) eq '';   # P Q=R S
+ok 65, substr($a,0,0) eq '';    # P=Q=R S
+ok 66, substr($a,0,5) eq '54321';# P=Q R=S
+ok 67, substr($a,0,7) eq '54321';# P=Q S R
+ok 68, substr($a,2,0) eq '';    # P Q=R S
+ok 69, substr($a,2,3) eq '321'; # P Q R=S
+ok 70, substr($a,5,0) eq '';    # P Q=R=S
+ok 71, substr($a,5,2) eq '';    # P Q=S R
+ok 72, substr($a,-7,-5) eq '';  # Q P=R S
+ok 73, substr($a,-7,-2) eq '543';# Q P R S
+ok 74, substr($a,-5,-5) eq '';  # P=Q=R S
+ok 75, substr($a,-5,-2) eq '543';# P=Q R S
+ok 76, substr($a,-3,-3) eq '';  # P Q=R S
+ok 77, substr($a,-3,-1) eq '32';# P Q R S
+
+$a = '';
+
+ok 78, substr($a,-2,2) eq '';   # Q P=R=S
+ok 79, substr($a,0,0) eq '';    # P=Q=R=S
+ok 80, substr($a,0,1) eq '';    # P=Q=S R
+ok 81, substr($a,-2,3) eq '';   # Q P=S R
+ok 82, substr($a,-2) eq '';     # Q P=R=S
+ok 83, substr($a,0) eq '';      # P=Q=R=S
+
+
+ok 84, substr($a,0,-1) eq '';   # R P=Q=S
+$b = substr($a,-2, 0) ; # warn  # Q=R P=S
+ok 85, $w-- == 1 ;
+eval{substr($a,-2, 0) = "" ; }; # Q=R P=S
+ok 86, $@ =~ /$FATAL_MSG/;
+
+$b = substr($a,-2, 1) ; # warn  # Q R P=S
+ok 87, $w-- == 1 ;
+eval{substr($a,-2, 1) = "" ; }; # Q R P=S
+ok 88, $@ =~ /$FATAL_MSG/;
+
+$b = substr($a,-2,-1) ; # warn  # Q R P=S
+ok 89, $w-- == 1 ;
+eval{substr($a,-2,-1) = "" ; }; # Q R P=S
+ok 90, $@ =~ /$FATAL_MSG/;
+
+$b = substr($a,-2,-2) ; # warn  # Q=R P=S
+ok 91, $w-- == 1 ;
+eval{substr($a,-2,-2) = "" ; }; # Q=R P=S
+ok 92, $@ =~ /$FATAL_MSG/;
+
+$b = substr($a, 1,-2) ; # warn  # R P=S Q
+ok 93, $w-- == 1 ;
+eval{substr($a, 1,-2) = "" ; }; # R P=S Q
+ok 94, $@ =~ /$FATAL_MSG/;
+
+$b = substr($a, 1, 1) ; # warn  # P=S Q R
+ok 95, $w-- == 1 ;
+eval{substr($a, 1, 1) = "" ; }; # P=S Q R
+ok 96, $@ =~ /$FATAL_MSG/;
+
+$b = substr($a, 1, 0) ;# warn   # P=S Q=R
+ok 97, $w-- == 1 ;
+eval{substr($a, 1, 0) = "" ; }; # P=S Q=R
+ok 98, $@ =~ /$FATAL_MSG/;
+
+$b = substr($a,1) ; # warning   # P=R=S Q
+ok 99, $w-- == 1 ;
+eval{substr($a,1) = "" ; };     # P=R=S Q
+ok 100, $@ =~ /$FATAL_MSG/;
+
+my $a = 'zxcvbnm';
+substr($a,2,0) = '';
+ok 101, $a eq 'zxcvbnm';
+substr($a,7,0) = '';
+ok 102, $a eq 'zxcvbnm';
+substr($a,5,0) = '';
+ok 103, $a eq 'zxcvbnm';
+substr($a,0,2) = 'pq';
+ok 104, $a eq 'pqcvbnm';
+substr($a,2,0) = 'r';
+ok 105, $a eq 'pqrcvbnm';
+substr($a,8,0) = 'asd';
+ok 106, $a eq 'pqrcvbnmasd';
+substr($a,0,2) = 'iop';
+ok 107, $a eq 'ioprcvbnmasd';
+substr($a,0,5) = 'fgh';
+ok 108, $a eq 'fghvbnmasd';
+substr($a,3,5) = 'jkl';
+ok 109, $a eq 'fghjklsd';
+substr($a,3,2) = '1234';
+ok 110, $a eq 'fgh1234lsd';
+
+
+# with lexicals (and in re-entered scopes)
+for (0,1) {
+  my $txt;
+  unless ($_) {
+    $txt = "Foo";
+    substr($txt, -1) = "X";
+    ok 111, $txt eq "FoX";
+  }
+  else {
+    substr($txt, 0, 1) = "X";
+    ok 112, $txt eq "X";
+  }
+}
+
+$w = 0 ;
+# coercion of references
+{
+  my $s = [];
+  substr($s, 0, 1) = 'Foo';
+  ok 113, substr($s,0,7) eq "FooRRAY" && !($w-=2);
+}
+
+# check no spurious warnings
+ok 114, $w == 0;
+
+# check new 4 arg replacement syntax
+$a = "abcxyz";
+$w = 0;
+ok 115, substr($a, 0, 3, "") eq "abc" && $a eq "xyz";
+ok 116, substr($a, 0, 0, "abc") eq "" && $a eq "abcxyz";
+ok 117, substr($a, 3, -1, "") eq "xy" && $a eq "abcz";
+
+ok 118, substr($a, 3, undef, "xy") eq "" && $a eq "abcxyz"
+                 && $w == 3;
+
+$w = 0;
+
+ok 119, substr($a, 3, 9999999, "") eq "xyz" && $a eq "abc";
+eval{substr($a, -99, 0, "") };
+ok 120, $@ =~ /$FATAL_MSG/;
+eval{substr($a, 99, 3, "") };
+ok 121, $@ =~ /$FATAL_MSG/;
+
+substr($a, 0, length($a), "foo");
+ok 122, $a eq "foo" && !$w;
+
+# using 4 arg substr as lvalue is a compile time error
+eval 'substr($a,0,0,"") = "abc"';
+ok 123, $@ && $@ =~ /Can't modify substr/ && $a eq "foo";
+
+$a = "abcdefgh";
+ok 124, sub { shift }->(substr($a, 0, 4, "xxxx")) eq 'abcd';
+ok 125, $a eq 'xxxxefgh';
+
+{
+    my $y = 10;
+    $y = "2" . $y;
+    ok 126, $y+0 == 210;
+}
+
+# utf8 sanity
+{
+    my $x = substr("a\x{263a}b",0);
+    ok 127, length($x) == 3;
+    $x = substr($x,1,1);
+    ok 128, $x eq "\x{263a}";
+    $x = $x x 2;
+    ok 129, length($x) == 2;
+    substr($x,0,1) = "abcd";
+    ok 130, $x eq "abcd\x{263a}";
+    ok 131, length($x) == 5;
+    $x = reverse $x;
+    ok 132, length($x) == 5;
+    ok 133, $x eq "\x{263a}dcba";
+
+    my $z = 10;
+    $z = "21\x{263a}" . $z;
+    ok 134, length($z) == 5;
+    ok 135, $z eq "21\x{263a}10";
+}
+
+# replacement should work on magical values
+require Tie::Scalar;
+my %data;
+tie $data{'a'}, 'Tie::StdScalar';  # makes $data{'a'} magical
+$data{a} = "firstlast";
+ok 136, substr($data{'a'}, 0, 5, "") eq "first" && $data{'a'} eq "last";
+
+# more utf8
+
+# The following two originally from Ignasi Roca.
+
+$x = "\xF1\xF2\xF3";
+substr($x, 0, 1) = "\x{100}"; # Ignasi had \x{FF}
+ok 137, length($x) == 3 &&
+        $x eq "\x{100}\xF2\xF3" &&
+        substr($x, 0, 1) eq "\x{100}" &&
+        substr($x, 1, 1) eq "\x{F2}" &&
+        substr($x, 2, 1) eq "\x{F3}";
+
+$x = "\xF1\xF2\xF3";
+substr($x, 0, 1) = "\x{100}\x{FF}"; # Ignasi had \x{FF}
+ok 138, length($x) == 4 &&
+        $x eq "\x{100}\x{FF}\xF2\xF3" &&
+        substr($x, 0, 1) eq "\x{100}" &&
+        substr($x, 1, 1) eq "\x{FF}" &&
+        substr($x, 2, 1) eq "\x{F2}" &&
+        substr($x, 3, 1) eq "\x{F3}";
+
+# more utf8 lval exercise
+
+$x = "\xF1\xF2\xF3";
+substr($x, 0, 2) = "\x{100}\xFF";
+ok 139, length($x) == 3 &&
+        $x eq "\x{100}\xFF\xF3" &&
+        substr($x, 0, 1) eq "\x{100}" &&
+        substr($x, 1, 1) eq "\x{FF}" &&
+        substr($x, 2, 1) eq "\x{F3}";
+
+$x = "\xF1\xF2\xF3";
+substr($x, 1, 1) = "\x{100}\xFF";
+ok 140, length($x) == 4 &&
+        $x eq "\xF1\x{100}\xFF\xF3" &&
+        substr($x, 0, 1) eq "\x{F1}" &&
+        substr($x, 1, 1) eq "\x{100}" &&
+        substr($x, 2, 1) eq "\x{FF}" &&
+        substr($x, 3, 1) eq "\x{F3}";
+
+$x = "\xF1\xF2\xF3";
+substr($x, 2, 1) = "\x{100}\xFF";
+ok 141, length($x) == 4 &&
+        $x eq "\xF1\xF2\x{100}\xFF" &&
+        substr($x, 0, 1) eq "\x{F1}" &&
+        substr($x, 1, 1) eq "\x{F2}" &&
+        substr($x, 2, 1) eq "\x{100}" &&
+        substr($x, 3, 1) eq "\x{FF}";
+
+$x = "\xF1\xF2\xF3";
+substr($x, 3, 1) = "\x{100}\xFF";
+ok 142, length($x) == 5 &&
+        $x eq "\xF1\xF2\xF3\x{100}\xFF" &&
+        substr($x, 0, 1) eq "\x{F1}" &&
+        substr($x, 1, 1) eq "\x{F2}" &&
+        substr($x, 2, 1) eq "\x{F3}" &&
+        substr($x, 3, 1) eq "\x{100}" &&
+        substr($x, 4, 1) eq "\x{FF}";
+
+$x = "\xF1\xF2\xF3";
+substr($x, -1, 1) = "\x{100}\xFF";
+ok 143, length($x) == 4 &&
+        $x eq "\xF1\xF2\x{100}\xFF" &&
+        substr($x, 0, 1) eq "\x{F1}" &&
+        substr($x, 1, 1) eq "\x{F2}" &&
+        substr($x, 2, 1) eq "\x{100}" &&
+        substr($x, 3, 1) eq "\x{FF}";
+
+$x = "\xF1\xF2\xF3";
+substr($x, -1, 0) = "\x{100}\xFF";
+ok 144, length($x) == 5 &&
+        $x eq "\xF1\xF2\x{100}\xFF\xF3" &&
+        substr($x, 0, 1) eq "\x{F1}" &&
+        substr($x, 1, 1) eq "\x{F2}" &&
+        substr($x, 2, 1) eq "\x{100}" &&
+        substr($x, 3, 1) eq "\x{FF}" &&
+        substr($x, 4, 1) eq "\x{F3}";
+
+$x = "\xF1\xF2\xF3";
+substr($x, 0, -1) = "\x{100}\xFF";
+ok 145, length($x) == 3 &&
+        $x eq "\x{100}\xFF\xF3" &&
+        substr($x, 0, 1) eq "\x{100}" &&
+        substr($x, 1, 1) eq "\x{FF}" &&
+        substr($x, 2, 1) eq "\x{F3}";
+
+$x = "\xF1\xF2\xF3";
+substr($x, 0, -2) = "\x{100}\xFF";
+ok 146, length($x) == 4 &&
+        $x eq "\x{100}\xFF\xF2\xF3" &&
+        substr($x, 0, 1) eq "\x{100}" &&
+        substr($x, 1, 1) eq "\x{FF}" &&
+        substr($x, 2, 1) eq "\x{F2}" &&
+        substr($x, 3, 1) eq "\x{F3}";
+
+$x = "\xF1\xF2\xF3";
+substr($x, 0, -3) = "\x{100}\xFF";
+ok 147, length($x) == 5 &&
+        $x eq "\x{100}\xFF\xF1\xF2\xF3" &&
+        substr($x, 0, 1) eq "\x{100}" &&
+        substr($x, 1, 1) eq "\x{FF}" &&
+        substr($x, 2, 1) eq "\x{F1}" &&
+        substr($x, 3, 1) eq "\x{F2}" &&
+        substr($x, 4, 1) eq "\x{F3}";
+
+$x = "\xF1\xF2\xF3";
+substr($x, 1, -1) = "\x{100}\xFF";
+ok 148, length($x) == 4 &&
+        $x eq "\xF1\x{100}\xFF\xF3" &&
+        substr($x, 0, 1) eq "\x{F1}" &&
+        substr($x, 1, 1) eq "\x{100}" &&
+        substr($x, 2, 1) eq "\x{FF}" &&
+        substr($x, 3, 1) eq "\x{F3}";
+
+$x = "\xF1\xF2\xF3";
+substr($x, -1, -1) = "\x{100}\xFF";
+ok 149, length($x) == 5 &&
+        $x eq "\xF1\xF2\x{100}\xFF\xF3" &&
+        substr($x, 0, 1) eq "\x{F1}" &&
+        substr($x, 1, 1) eq "\x{F2}" &&
+        substr($x, 2, 1) eq "\x{100}" &&
+        substr($x, 3, 1) eq "\x{FF}" &&
+        substr($x, 4, 1) eq "\x{F3}";
+
+# And tests for already-UTF8 one
+
+$x = "\x{101}\x{F2}\x{F3}";
+substr($x, 0, 1) = "\x{100}";
+ok 150, length($x) == 3 &&
+        $x eq "\x{100}\xF2\xF3" &&
+        substr($x, 0, 1) eq "\x{100}" &&
+        substr($x, 1, 1) eq "\x{F2}" &&
+        substr($x, 2, 1) eq "\x{F3}";
+
+$x = "\x{101}\x{F2}\x{F3}";
+substr($x, 0, 1) = "\x{100}\x{FF}";
+ok 151, length($x) == 4 &&
+        $x eq "\x{100}\x{FF}\xF2\xF3" &&
+        substr($x, 0, 1) eq "\x{100}" &&
+        substr($x, 1, 1) eq "\x{FF}" &&
+        substr($x, 2, 1) eq "\x{F2}" &&
+        substr($x, 3, 1) eq "\x{F3}";
+
+$x = "\x{101}\x{F2}\x{F3}";
+substr($x, 0, 2) = "\x{100}\xFF";
+ok 152, length($x) == 3 &&
+        $x eq "\x{100}\xFF\xF3" &&
+        substr($x, 0, 1) eq "\x{100}" &&
+        substr($x, 1, 1) eq "\x{FF}" &&
+        substr($x, 2, 1) eq "\x{F3}";
+
+$x = "\x{101}\x{F2}\x{F3}";
+substr($x, 1, 1) = "\x{100}\xFF";
+ok 153, length($x) == 4 &&
+        $x eq "\x{101}\x{100}\xFF\xF3" &&
+        substr($x, 0, 1) eq "\x{101}" &&
+        substr($x, 1, 1) eq "\x{100}" &&
+        substr($x, 2, 1) eq "\x{FF}" &&
+        substr($x, 3, 1) eq "\x{F3}";
+
+$x = "\x{101}\x{F2}\x{F3}";
+substr($x, 2, 1) = "\x{100}\xFF";
+ok 154, length($x) == 4 &&
+        $x eq "\x{101}\xF2\x{100}\xFF" &&
+        substr($x, 0, 1) eq "\x{101}" &&
+        substr($x, 1, 1) eq "\x{F2}" &&
+        substr($x, 2, 1) eq "\x{100}" &&
+        substr($x, 3, 1) eq "\x{FF}";
+
+$x = "\x{101}\x{F2}\x{F3}";
+substr($x, 3, 1) = "\x{100}\xFF";
+ok 155, length($x) == 5 &&
+        $x eq "\x{101}\x{F2}\x{F3}\x{100}\xFF" &&
+        substr($x, 0, 1) eq "\x{101}" &&
+        substr($x, 1, 1) eq "\x{F2}" &&
+        substr($x, 2, 1) eq "\x{F3}" &&
+        substr($x, 3, 1) eq "\x{100}" &&
+        substr($x, 4, 1) eq "\x{FF}";
+
+$x = "\x{101}\x{F2}\x{F3}";
+substr($x, -1, 1) = "\x{100}\xFF";
+ok 156, length($x) == 4 &&
+        $x eq "\x{101}\xF2\x{100}\xFF" &&
+        substr($x, 0, 1) eq "\x{101}" &&
+        substr($x, 1, 1) eq "\x{F2}" &&
+        substr($x, 2, 1) eq "\x{100}" &&
+        substr($x, 3, 1) eq "\x{FF}";
+
+$x = "\x{101}\x{F2}\x{F3}";
+substr($x, -1, 0) = "\x{100}\xFF";
+ok 157, length($x) == 5 &&
+        $x eq "\x{101}\xF2\x{100}\xFF\xF3" &&
+        substr($x, 0, 1) eq "\x{101}" &&
+        substr($x, 1, 1) eq "\x{F2}" &&
+        substr($x, 2, 1) eq "\x{100}" &&
+        substr($x, 3, 1) eq "\x{FF}" &&
+        substr($x, 4, 1) eq "\x{F3}";
+
+$x = "\x{101}\x{F2}\x{F3}";
+substr($x, 0, -1) = "\x{100}\xFF";
+ok 158, length($x) == 3 &&
+        $x eq "\x{100}\xFF\xF3" &&
+        substr($x, 0, 1) eq "\x{100}" &&
+        substr($x, 1, 1) eq "\x{FF}" &&
+        substr($x, 2, 1) eq "\x{F3}";
+
+$x = "\x{101}\x{F2}\x{F3}";
+substr($x, 0, -2) = "\x{100}\xFF";
+ok 159, length($x) == 4 &&
+        $x eq "\x{100}\xFF\xF2\xF3" &&
+        substr($x, 0, 1) eq "\x{100}" &&
+        substr($x, 1, 1) eq "\x{FF}" &&
+        substr($x, 2, 1) eq "\x{F2}" &&
+        substr($x, 3, 1) eq "\x{F3}";
+
+$x = "\x{101}\x{F2}\x{F3}";
+substr($x, 0, -3) = "\x{100}\xFF";
+ok 160, length($x) == 5 &&
+        $x eq "\x{100}\xFF\x{101}\x{F2}\x{F3}" &&
+        substr($x, 0, 1) eq "\x{100}" &&
+        substr($x, 1, 1) eq "\x{FF}" &&
+        substr($x, 2, 1) eq "\x{101}" &&
+        substr($x, 3, 1) eq "\x{F2}" &&
+        substr($x, 4, 1) eq "\x{F3}";
+
+$x = "\x{101}\x{F2}\x{F3}";
+substr($x, 1, -1) = "\x{100}\xFF";
+ok 161, length($x) == 4 &&
+        $x eq "\x{101}\x{100}\xFF\xF3" &&
+        substr($x, 0, 1) eq "\x{101}" &&
+        substr($x, 1, 1) eq "\x{100}" &&
+        substr($x, 2, 1) eq "\x{FF}" &&
+        substr($x, 3, 1) eq "\x{F3}";
+
+$x = "\x{101}\x{F2}\x{F3}";
+substr($x, -1, -1) = "\x{100}\xFF";
+ok 162, length($x) == 5 &&
+        $x eq "\x{101}\xF2\x{100}\xFF\xF3" &&
+        substr($x, 0, 1) eq "\x{101}" &&
+        substr($x, 1, 1) eq "\x{F2}" &&
+        substr($x, 2, 1) eq "\x{100}" &&
+        substr($x, 3, 1) eq "\x{FF}" &&
+        substr($x, 4, 1) eq "\x{F3}";
+
+substr($x = "ab", 0, 0, "\x{100}\x{200}");
+ok 163, $x eq "\x{100}\x{200}ab";
+
+substr($x = "\x{100}\x{200}", 0, 0, "ab");
+ok 164, $x eq "ab\x{100}\x{200}";
+
+substr($x = "ab", 1, 0, "\x{100}\x{200}");
+ok 165, $x eq "a\x{100}\x{200}b";
+
+substr($x = "\x{100}\x{200}", 1, 0, "ab");
+ok 166, $x eq "\x{100}ab\x{200}";
+
+substr($x = "ab", 2, 0, "\x{100}\x{200}");
+ok 167, $x eq "ab\x{100}\x{200}";
+
+substr($x = "\x{100}\x{200}", 2, 0, "ab");
+ok 168, $x eq "\x{100}\x{200}ab";
+
+substr($x = "\xFFb", 0, 0, "\x{100}\x{200}");
+ok 169, $x eq "\x{100}\x{200}\xFFb";
+
+substr($x = "\x{100}\x{200}", 0, 0, "\xFFb");
+ok 170, $x eq "\xFFb\x{100}\x{200}";
+
+substr($x = "\xFFb", 1, 0, "\x{100}\x{200}");
+ok 171, $x eq "\xFF\x{100}\x{200}b";
+
+substr($x = "\x{100}\x{200}", 1, 0, "\xFFb");
+ok 172, $x eq "\x{100}\xFFb\x{200}";
+
+substr($x = "\xFFb", 2, 0, "\x{100}\x{200}");
+ok 173, $x eq "\xFFb\x{100}\x{200}";
+
+substr($x = "\x{100}\x{200}", 2, 0, "\xFFb");
+ok 174, $x eq "\x{100}\x{200}\xFFb";
+