Playwright's expect() costs ~3 ms a call: 160,000 checks in a loop ran a test past 5 min; one check after it: 7 s

pnpm exec playwright test --config playwright.unit.config.ts tests/unit/investments.spec.ts → "10 passed (7.0s)"; the whole unit suite → "52 passed (14.0s)".

@playwright/test@>=1.40

a synchronous expect(x).toBeLessThanOrEqual(y) costs about as much as the comparison, so 4 symbols × 20,000 ticks × 2 checks is nothing.

pnpm test:unit was killed by its 400 s timeout; run alone, the spec ended with "the walk is bounded … Error: worker process exited unexpectedly (code=143, signal=null)" after 4.9 min while the other 8 tests had passed.

not traced into Playwright's source. Measured alone: 20,000 expect(Math.abs(Math.sin(i))).toBeLessThanOrEqual(1) calls took 58,080.8 ms, the loop without expect 9.1 ms, about 2.9 ms a call (other specs running); each expect being reported as a step is the likely cost.

4.9 min and killed → 7.0 s for the spec; the micro-measurement above (a throwaway spec, deleted after); Node 22.