In another thread, Michal Bolton gave some interesting ideas on other activities that you can automate in the broader field of testing, which isn’t testing itself:
Programs for generating data; for modeling business rules and creating a comparable-product oracle; for obfuscating real-life data; for converting and/or massaging test data from one format to another; for visualizing coverage; for setup and configuration (and for checking whether the system is in an appropriately set-up state); for sorting and searching logs; for obtaining more extensive coverage of specific functions, either by randomizing or iterating through all the possible values for a given setting.