diff --git a/testing/parameters.c b/testing/parameters.c
index b94b54701591c29a8faf16ab5dd8803011477eba..8f6e1f4adb390c137411f0abf2222685b56b2415 100644
--- a/testing/parameters.c
+++ b/testing/parameters.c
@@ -305,7 +305,7 @@ void
 parameters_read( parameter_t *param,
                  const char  *values )
 {
-    int range = ( strchr( values, ':' ) != NULL );
+    int range = (values != NULL) && ( strchr( values, ':' ) != NULL );
 
     /* If we have a ranged of integer values */
     if ( range )