Approved workflow

The brief requires 'events for every state change'. The suite never uses expectEmit or reads logs, so PledgeCreated, CheckedIn and PledgeSettled are unverified in emission, indexed fields and argument values. The frontend and indexers depend on these events for progress and forfeit display.

No emit is missing in the current source; the gap is that the tests would not notice if one were removed or changed.

The brief asks for 'reentrancy through a malicious token'. ReentrantToken re-enters only from transferFrom during createPledge. Its transfer() returns true without any callback, so the settlement path (withdraw -> _safeTransfer to pledger and beneficiary) is never exercised with a re-entering token.

The settled-before-transfer ordering and the nonReentrant guard on withdraw and checkIn are therefore unverified. The current source is correct here; the suite would not catch a regression.

testRejectsInvalidCreationParametersAndWrongAmounts covers weeks==0, beneficiary==msg.sender, a non-divisible stake and an empty goal only.

Untested: weeks > MAX_WEEKS (53), stake == 0, beneficiary == address(0), constructor InvalidToken (zero address and EOA), UnknownPledge for withdraw, checkIn, endTime and currentWeek, insufficient allowance or balance on createPledge, and any assertion on currentWeek(). The all-missed case (full stake forfeited, nothing returned) and a week-51 check-in at the 52-week bitmap boundary are also absent.

The Pledge token has only one supply/decimals test: transferFrom allowance decrement, the max-allowance path, InsufficientBalance, InsufficientAllowance and InvalidReceiver are never tested, even though PLDG is the asset being custodied.

createPledge rejects only address(0) and msg.sender as beneficiary. A beneficiary equal to address(this) or to the token address is accepted. On withdraw the forfeited amount is transferred to that address and can never be moved again, because HabitPledge has no rescue function (correct under the no-admin requirement) and the token has no recovery path.

Harm is limited to the pledger's own stake: accounting is per-pledge, and other pledges are unaffected. This is a footgun that the frontend or contract could reject with one additional check, not a theft.

The brief specifies 'a number of weekly check-ins' without an upper bound and 'withdraw at the end'. The implementation limits weeks to 1..52 and allows settlement only at or after startTime + weeks*7 days (not right after the last check-in). Both are consistent and documented in docs/contracts.html, and neither loses funds, but a website that accepts a larger weeks value or offers early withdrawal would hit InvalidWeeks or PledgeActive.

This is not a defect in the contract; it is an interface constraint for the web assignment.

The malicious-token test only re-enters createPledge from transferFrom. The nonReentrant guards on withdraw and checkIn, and the settlement-time reentrancy path via transfer, have no test, although the brief requires reentrancy through a malicious token.

The approved design leaves these points open.

1. MAX_WEEKS=52 and the requirement that stake be divisible by weeksCount are limits the brief does not state.
2. The beneficiary != msg.sender check is trivially bypassed with a second address.
3. A pledger's full return is only claimable after endTime, since the last window closes then. (4) withdraw() is callable by anyone and always pays the pledger and beneficiary, so a third party cannot redirect funds.