diff --git a/tests/tcctest.c b/tests/tcctest.c
index cc8ffd8..30c9518 100644
--- a/tests/tcctest.c
+++ b/tests/tcctest.c
@@ -2582,6 +2582,8 @@ void builtin_test(void)
     COMPAT_TYPE(int *, void *);
     COMPAT_TYPE(int *, const int *);
     COMPAT_TYPE(char *, unsigned char *);
+    COMPAT_TYPE(char *, signed char *);
+    COMPAT_TYPE(char *, char *);
 /* space is needed because tcc preprocessor introduces a space between each token */
     COMPAT_TYPE(char * *, void *); 
 #endif