# The browser suite is flaky under load — UNRESOLVED, and owned by design-dev

_2026-09-23 · booth_

⚠ **OPEN. Not fixed. Do not read a green suite as proof of anything without
re-running it.**

## What is observed, with its limits

**Three different browser tests** have each failed once under full-suite load
while passing repeatedly in isolation:

| test | owner | isolation | full suite |
|---|---|---|---|
| `test_the_keyboard_flag_actually_submits` | booth-dev | 5/5 pass | 1 failure |
| `test_a_failed_save_says_so_reloads_and_never_re_posts` | design-dev | 3/3 pass | 1 failure |
| `test_the_review_keys_judge_in_place_and_stay_out_of_the_note` | design-dev | 10/10 + 5/5 pass | 1 in ~9 |

Three different tests points at **the environment under contention**, not at any
one test. That is a direction, not a finding.

## Two real defects found chasing it — NEITHER PROVEN TO BE THE CAUSE

1. **A keypress race.** The flag test fired `ArrowRight` and `f` back to back,
   assuming the first had finished — but `focus()` does a `scrollIntoView`, so
   under load `f` could arrive with no cursor set. Now waits for
   `figure.item.is-cursor`.
2. **A port TOCTOU in BOTH browser fixtures.** Each did `bind → getsockname →
   CLOSE → hand uvicorn the port NUMBER`, leaving a window for the kernel to
   give that port away — and this suite runs two browser files that each start a
   server per test, so the competitor is the other file. The bound socket is now
   passed to `server.run(sockets=[sock])`.

**Since those fixes: one failure in three full runs. n=3 CANNOT distinguish
that from the prior rate, and no claim of improvement is made.**

## Who owns it and what the method is

**The operator ruled: "let him diagnose it properly."** design-dev owns it. His
method: a trace hook keeping a Playwright trace (screenshots + DOM snapshots)
for every browser test that fails, captured **from the run that fails**, then
full-suite runs until red and the artefact decides. Test-only infra, on his
branch as its own commit.

⚠ **The methodological trap, and why the artefact must come from the full
suite:** the failure only reproduces there. A narrowed repro that passes proves
nothing and will be mistaken for a fix.