diff --git a/test/dummytest.c b/test/dummytest.c
index f98f003ef98e0c57e190b13294bc6198c41beb24..5b4467e042bb7f193cd5c5bc18355445af2de12b 100644
--- a/test/dummytest.c
+++ b/test/dummytest.c
@@ -8,7 +8,7 @@
 
 int main(int argc, char *argv[])
 	{
-	char *p, *q, *program;
+	char *p, *q = 0, *program;
 
 	p = strrchr(argv[0], '/');
 	if (!p) p = strrchr(argv[0], '\\');
@@ -34,7 +34,8 @@ int main(int argc, char *argv[])
 		}
 
 	for(p = program; *p; p++)
-		if (islower(*p)) *p = toupper(*p);
+		if (islower((unsigned char)(*p)))
+			*p = toupper((unsigned char)(*p));
 
 	q = strstr(program, "TEST");
 	if (q > p && q[-1] == '_') q--;