What are you trying to accomplish with the campaign?
The simplest way to test is remove any actions in the campaign that could cause problems (e.g. data changes, email sends, alerts, etc). So for instance if you just want to see the possible affected leads, you could simply generate a list and spot check it.
If you're looking to test the flow of everything, then just change the smart list filters to only include a test lead (ideally you). Then you can run through entire flow and check that lead's activity log to make sure everything fired properly.