S6 — End-to-end input-integrity test suite (through the manager seam) #57

Epic: #51 · S6 · depends on #53/#52/#54/#55/#56 (S1–S5) · story testing

Problem

The unit tests cover each invariant on primitives; this story proves the guards fire end-to-end through the manager on synthetic data (the integration layer above each story's own unit tests).

Work — one tests/test_input_integrity_e2e*.py:

• Coverage (S1/C-34): correct region count passes; under/over raises.
• Observed range (S2/C-26): a month beyond last_valid_month_id is not delivered as zero (skip/xfail with reason if the companion isn't landed).
• Forecast identity (S3/C-25): a decoy forecast file is rejected.
• land_gaul (S4/C-30): 64,736 + 82 fixture; injected unassigned cell crashes loud.
• Provenance (S5/C-15): upload metadata carries the structured fields.

Acceptance criteria

• The module covers all five through the manager seam; green where implemented, explicit skip/xfail (with reason) where gated.
• ruff + full suite green; the design-contract stubs are all real (no remaining input-integrity xfails except C-40-deferred manager inheritance).

Files

tests/test_input_integrity_e2e*.py (new).