Root cause: addParticipant appended participant to participants[] without
checking id uniqueness. Two participants with same id in array. On
togglePause resume, turnOrderIds rebuilt via sort → dup id appears twice.
nextTurn then stuck repeating that id (rotation breaks).
This was the enabling step for BUG-1's full corruption (audit chain):
pause blocks advance → totalTurns frozen → addParticipant re-adds
same r${totalTurns} id → resume dup → nextTurn stuck.
Fix: throw on duplicate id in addParticipant. Caller must use fresh id
(crypto.randomUUID in App, replay already does).
Evidence:
- Test: 'addParticipant rejects duplicate id' (was test.skip, now live).
- Pre-fix: 1 RED (Received function did not throw).
- Post-fix: 50 green (shared), 23 green (server), 62 green (FE).
- Reachability in normal app: low (App uses crypto.randomUUID) but no
guard existed before. Defensive + unblocks BUG-1 isolation.
No other behavior changed.
Move all test files out of source dirs into per-workspace tests/:
- shared/tests/ (3 unit test files)
- server/tests/ (1 integration test)
- src/tests/ (8 characterization + scenario tests + testHelpers)
Fix all relative import paths (App, storage, __mocks__, testHelpers).
Fix jest.config testMatch globs in shared/ and server/ (rootDir +
<rootDir>/tests pattern).
Delete scripts/repro-pause-bug.js (debug scratch, superseded by
turn.pause-add.test.js).
Keep scripts/replay-combat.js + scripts/audit-rotation.js as manual
demo/exploratory tools (NOT unit tests, not deterministic).
No logic changes. All green: shared 49 + 1 validated RED, server 23,
FE 62. Scenario test unchanged (240s timeout, pre-existing slow).
david raistrick