I may get flamed for making this quick and dirty suggestion but it's worked for me. One way to easily test the fixture is to effectively plug the black and white wires of the fixture into an electrical outlet.
By "effectively" I actually mean do this:
1. Put the fixture in a safe location where it won't cause any problems SHOULD it cause a short etc. If you can do this outside on a concrete sidewalk etc... all the better. It should be away from people, pets, and flamable items to be safe... but close enough where you can see it when the light (hopefully) comes on.
2. Find a good heavy outdoor extension cord. With the cord unplugged, firmly insert the black and white fixture wires into the female end of the cord (one wire in each vertical slot). If the fixture has a ground wire you can place that into the round hole of the cord. Be sure the wires are well inserted to make good contact.
3. Plug the extension cord into a working outlet. If you have access to a switched recepticle, all the better. That way you can control the power from a wall switch and keep even more distance. The important part is to use a good heavy cord and a grounded outlet.
4. Check the light. If it doesn't work, unplug the cord and check the wires and try again etc until you are satisfied that the fixture is bad. Most likely it will work and you can rule it out as your problem.
Again, this probably isn't OSHA approved or for the faint of heart... but it works and CAN be done safely.