Pex and previously written tests

I am working a project with many NUnit tests, that were already written long time ago. What is the best way to run Pex on these tests and extend开发者_如何学运维 them? I try to run Pex on the methods that are being tested, but Pex wants to create new projects and new tests, and doesn't pick up the old ones.

With Pex, you need to create tests that take in parameters. Pex will then look at these methods kinda like they were row tests, and then generate its own tests to maximize code coverage.