[cranium]

It would work for most "classical" software development. In this case, the author talks about conformance tests (a HUGE collection) from an external vendor. Most of them will fail at first, then you make them pass slowly but steadily.

The problem becomes: I want to know if there are significant regressions in the vendor tests, ie. tests that were green for a long time and suddenly changed. You could flag any test that became green at some point as "required" to pass the CI, but then you have tests that randomly succeed or fail depending on code you have not yet written (eg. locking around concurrent structures). Marking these tests manually is impractical and could definitively be replaced by tooling that supports some statistical modeling of success/failure.

You may have the best testing strategy for internal code but as long as you have to test against these conformance tests it's simply unfeasible to say "sorry, only green allowed".