rem: BOOST_CHECK(add_returned_null);
add: BOOST_TEST(add_returned_null);
context: narrow_free_functions_tests(){    symbols<>   sym;#define add_returned_non_null_value (res!=0)#define add_returned_null (res==0)#define find_returned_non_null_value (res!=0)#define find_returned_null (res==0)    int *res = add(sym,"pineapple");    BOOST_CHECK(add_returned_non_null_value);    res = add(sym,"pineapple");    BOOST_CHECK(add_returned_null);    res = find(sym, "pineapple");    BOOST_CHECK(find_returned_non_null_value);    res = find(sym, "banana");    BOOST_CHECK(find_returned_null);};