1 files changed, 3 insertions, 0 deletions
diff --git a/tests/format.test b/tests/format.test
index c47774a..8cabbf1 100644
--- a/tests/format.test
+++ b/tests/format.test
@@ -402,6 +402,9 @@ test format-8.26 {Undocumented formats} -body {
 test format-8.27 {Undocumented formats} -constraints pointerIs64bit -body {
     format "%p %#llx" [expr {2**33}] [expr {2**33}]
 } -result {0x200000000 0x200000000}
+test format-8.28 {Internal use of TCL_COMBINE flag should not be visiable at script level} {
+    format %c 0x10000041
+} \uFFFD
 
 test format-9.1 {long result} {
     set a {1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ 1 2 3 4 5 6 7 8 9 0 a b c d e f g h i j k l m n o p q r s t u v w x y z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z}