diff --git a/Source/kwsys/testhash.cxx b/Source/kwsys/testhash.cxx
index 609f20d4b..dc3c66015 100644
--- a/Source/kwsys/testhash.cxx
+++ b/Source/kwsys/testhash.cxx
@@ -21,6 +21,7 @@
 #if 0
 # include "hash_map.hxx.in"
 # include "hash_set.hxx.in"
+# include "hashtable.hxx.in"
 # include "kwsys_ios_iostream.h.in"
 #endif