The following error appears when parsing SQLs with NULL Literals:
ERROR The column list specified by the Changed by Program data structure is incompatible with the column list specified by the Expected Results data structure. Make sure that the table and/or query on both "sides" of your outcome return a compatible set of column values.
Version 1.6.0 of Code Tester was not able to properly parse a data type from the NULL value in the select list.
Issue fixed in version 1.6.1. This version of Quest Code Tester for Oracle can be downloaded here.