Pex users: what are your Impressions of Pex and Automated Exploratory Testing in general?

Question

Those of you who have used Pex, what do you think its advantages and disadvantages are of Pex as a tool?

Also, what do you think are the advantages and disadvantages of "Automated Exploratory Testing" in general, as a supplement to TDD/Unit Testing?

Answer 1

Pex lets your write parameterized unit tests. In that sense, it totally fits into the TDD/unit testing flow: write the test, have Pex 'explore' it, find some failing tests, fix the code, and so forth.

The big advantage is that you can express your tests for classes of inputs, not just a couple hard-coded values. This gives more expressiveness for writing tests and also forces to think about the invariant/expectation that your code should fullfill (i.e. it's harder to write assertions).