1 files changed, 1 insertions, 1 deletions
diff --git a/t/io/dup.t b/t/io/dup.t
index 91e4f26f21..8247b8e6ef 100755
--- a/t/io/dup.t
+++ b/t/io/dup.t
@@ -96,7 +96,7 @@ SKIP: {
     isnt(fileno(F), fileno(STDOUT));
     close F;
 
-    ok(open(F, "<&=STDIN"));
+    ok(open(F, "<&=STDIN")) or _diag $!;
     is(fileno(F), fileno(STDIN));
     close F;