Frontend Testing Unlock reliable confidence fast: enable safe refactors by choosing the right test layer, making the app observable, and eliminating nondeterminism so failures are actionable. Philosophy: Confidence Per Minute Frontend tests fail for two reasons: the product is broken, or the test is lying. Your job is to maximize signal and minimize “test is lying”. Before writing a test, ask : - What user risk am I covering (money, progression, auth, data loss, “can’t start” crashes)? - What’s the narrowest layer that catches this bug class (pure logic vs UI vs full browser)? - What nondeter…