1. A method of performing comparative testing on contents of a file, said method comprising: parsing contents of the file into a data structure; generating problem objects for errors in the contents of the file, wherein each problem object indicates a class and a location in the data structure; comparing the problem objects of the contents of the file to problem objects of at least one other version of the file; and marking the problem objects of the contents of the file with a level of significance based on the comparison.