Review of the Task 1 commit approved the implementation but flagged the third test in mailOutcome.test.ts as a defect carried over from the brief: it set SMTP_USER, SMTP_PASSWORD, and an allowlist the recipient satisfied, so sendMail fell through both early-return guards and reached the real transporter, opening a live TLS connection to smtp.gmail.com:465. The .catch(() => 'threw') wrapper hid a fast auth rejection, a slow timeout, or an accidental real send equally, and on a restricted CI runner it would hang to the Jest timeout rather than fail fast.
The fix deletes that test rather than replacing it. What it was trying to prove — that an allowlisted recipient is not blocked — is already covered hermetically by backend/tests/unit/mailAllowlist.test.ts, which exercises isAllowedRecipient directly across exact matches, plus-suffixes, domains, and refusals. The other two tests in mailOutcome.test.ts are untouched; they cover the two paths that return early, which is the entire point of the change, and neither one reaches the transporter.
The file's top doc comment is updated to match: it now says only the two skip paths are covered here, names mailAllowlist.test.ts as where the allowlist's own behaviour is tested, and spells out why a third test that reaches the transporter does not belong in this file, so nobody adds one back.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
It returned Promise<void> and returned early in two cases that were indistinguishable from success at the call site: no SMTP credentials, and a recipient outside MAIL_ALLOWLIST. A caller could therefore report that it had emailed somebody a message nobody would ever receive, and in QA — which restricts delivery deliberately, as its entire safety property — that is the normal case rather than an edge one.
It now returns a MailOutcome saying which of the three happened. No existing caller changes: there are seven and every one ignores the result, so this is additive. Re-deriving the answer at a second site would have duplicated isAllowedRecipient and the SMTP check, which is exactly the drift the guard-in-one-place comment above them exists to prevent.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
bermudalambandClaude Opus 5