Normalize maintenance-slot requests to explicit UTC intervals
A technician's daylight-saving transition produces two appointments labelled 01:30 with no offset in the booking request.
- Focused work estimate
- 1h 15m + prerequisites
- Priority in the scenario
- Medium
- Engineering practice
- Time zones · Validation
Estimated field mix
- Backend70%
- API design30%
Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence.
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Project context
A fictional equipment service books maintenance visits. Expiring checkout holds and reschedules occasionally double-book a technician.
Setup prerequisites
- Build synthetic technicians, slots and booking records.
- Use an injectable clock and separate clients for concurrency probes.
Preceding work
No earlier ticket is required. Complete the project setup above.
Acceptance criteria
- Require start, end and explicit offset.
- Reject end-before-start and zero-duration intervals.
- Persist UTC while returning the requested display zone separately.
Implementation constraints
- Create synthetic ambiguous-hour cases rather than reading real calendars.
Verification to include
- Round-trip two different offsets for the repeated hour.
- Reject an offset-free repeated-hour request.
Deliverables
- Slot input contract and DST cases
Rollout and recovery
Add validation before new slot creation; retain original timestamps for existing rows.
Value of the work
For the engineer: Practice resource allocation, interval conflicts and durable workflows.
For the team: Review scheduling correctness and recovery before exposing scarce capacity.
Evidence boundaries
Outcome Evidence: Tests, patches, and runbooks are requested deliverables. They become Outcome Evidence only through a qualified Mission and immutable Evidence IDs.
Ownership Evidence: Independent adaptation must be observed under a declared verification policy and cite immutable Evidence IDs. Completing a planning ticket establishes no Ownership Evidence.