There isn't really a way to test one but you can visually inspect it. Pull the Antifreeze reservoir up out of the way (no tools required) There is a 12 or 13mm bolt you remove on the front of the cover. Pull the front part of the cover up and out. You can then look down in and see the timing belt and give a general assessment of the condition. Look the closest at the underside of the belt (it wraps up around some pulley's etc so it's fairly easy). You'll be looking for any sign of seperation in the belt or any cracking. Given the year of your car it probably is deteriorated and needs replacement. In my experience they go from time and not really mileage (1993 Escort T-belt failed @ 7 years 105kmi, preventative changed it a year later @ 225kmi and it was still in new specs, similar experience with Subaru) Although for the surprisingly low cost I will always do it as preventative maintanence on my 850 since I want to pass the 500kmi mark... better safe than sorry.
--
'94 855 5spd 'Drew' 201,500 Miles