They spent 95% effort to decide how many banks to fail, the other 5% to design the test to fail 7 banks. Why seven? They argued a lot. Final, they just picked a number as god did.
Don't be so gullible. The overarching purpose of these tests (both US and Europe) was not about revealing the truth but to fool the public and, in the process, relieve the market concerns. Just what the hell will the government do when a large bank is on the verge of collapsing? For example, do you believe the regulators will swoop in and quietly shut down Goldman Sachs over the weekend like they do with community banks? Get real. There's nothing stressful about the stress test. That's the whole point.