1. A method of performing comparative testing on contents of a program code file, said method comprising: parsing, by a computing device executing a testing tool, the contents of a new version of the program code file into a tree data structure; generating, by the computing device, problem objects for errors in the contents of the new version of the program code file, wherein each problem object comprises a class and a pointer to a location in the tree data structure, wherein the class is used to classify an error in the new version of the program code file; comparing the problem objects of the contents of the new version of the program code file to problem objects of a previous version of the program code file; and marking at least one of the problem objects of the contents of the new version of the program code file or the problem objects of the previous version of the program code file with a level of significance based on the comparison, the level of significance reflecting a tolerability of the problem objects in the program code file, wherein problem objects that are present in only the new version of the program code file are marked as new problems and problem objects that are present in only the previous version of the program code file are marked as resolved problems.