Fix the syswrite downgrade bug of

[perl #23428] Somethings rotten in unicode semantics

p4raw-id: //depot/perl@20804

1 files changed, 10 insertions, 1 deletions

diff --git a/t/io/utf8.t b/t/io/utf8.t
index 6a24c51e7e..6b189ee352 100755
--- a/t/io/utf8.t
+++ b/t/io/utf8.t
@@ -13,7 +13,7 @@ no utf8; # needed for use utf8 not griping about the raw octets
 
 require "./test.pl";
 
-plan(tests => 49);
+plan(tests => 51);
 
 $| = 1;
 
@@ -301,6 +301,15 @@ ok( 1 );
     # last test here 49
 }
 
+{
+    # [perl #23428] Somethings rotten in unicode semantics
+    open F, ">a";
+    binmode F, ":utf8";
+    syswrite(F, $a = chr(0x100));
+    is( ord($a), 0x100, '23428 syswrite should not downgrade scalar' );
+    like( $a, qr/^\w+/, '23428 syswrite should not downgrade scalar' );
+}
+
 # sysread() and syswrite() tested in lib/open.t since Fcntl is used
 
 END {