diff --git a/build/Makefile.in b/build/Makefile.in
index 0294671..9d6b1b7 100644
--- a/build/Makefile.in
+++ b/build/Makefile.in
@@ -81,6 +81,7 @@ $(TCLLEXPAD_PIR): src/TclLexPad.pm
 
 TEST_FILES = \
   t/sanity.t \
+  t/cmd_concat.t \
   t/cmd_llength.t \
   t/cmd_join.t \
   t/cmd_split.t