make some t/op/write.t failures more verbose

p4raw-id: //depot/perl@22203

diff --git a/t/op/write.t b/t/op/write.t
index 4f38bfb..ae9f8a5 100755 (executable)
--- a/t/op/write.t
+++ b/t/op/write.t
@@ -487,7 +487,9 @@ for my $tref ( @NumTests ){
         my $writeres = swrite( $writefmt, $val );
         $nt++;
 
-        print $expected eq $writeres ? "ok $nt\n" : "not ok $nt\n";
+        print $expected eq $writeres
+           ? "ok $nt\n"
+           : "not ok $nt\n# f=[$writefmt] exp=[$expected] got=[$writeres]\n";
     }
 }