little test-helper cosmetics

src/lib/test/test-helper.hpp

@@ -133,11 +133,11 @@ namespace test{
           try                                                                   \
             {                                                                   \
               ERRONEOUS_STATEMENT ;                                             \
-              NOTREACHED();               \
+              NOTREACHED("'%s' resisted to fail", #ERRONEOUS_STATEMENT);        \
             }                                                                   \
           catch (...)                                                           \
             {                                                                   \
-              ASSERT (lumiera_error () == LUMIERA_ERROR_##ERROR_ID ); \
+              CHECK (lumiera_error_expect (LUMIERA_ERROR_##ERROR_ID));          \
             }
 
 #endif