What? No. Please tell me this is not how you test your own code — only cases for “happy path”, ignore exceptions, no corner case coverage. Line coverage goals of 10% or so.

Waymo has a lot of miles in quiet suburbs with broad streets and light traffic. How has that helped them when they get to SF?

Didn't Waymo start testing without backup drivers in Phoenix, which is exactly as you describe (and also has clear weather nearly every day)? I think they only moved on to SF after deciding things worked well enough there.

If subjects aren't passing tests, the solution is to make the tests easier?

(Remember this the next time someone says "teachers are the reason our kids are dumb".)