Using a seed with the "random" is exactly how you get to pseudo-random, which gives the same sequence everytime, and is absolutely fine for tests.

If you want to have the build (test) result feedback to save the input, that's an ok goal but I think it's hard to pull off: now you have your build making commits to source control (causing another build), or you have test data stored somewhere else not in source (when really, it should be part of source).