[EPAC-1875]: Add integration tests for POST /api/v1/device/register handler

[riddim-developer-bot]

Why

The device-register upsert SQL — including the ON CONFLICT DO UPDATE clause and TEXT[] array storage for topic_ids / bill_ids — was only exercised by mocked-repository tests. Schema drift, array serialization bugs, or a removed ON CONFLICT clause would not fail existing tests. This PR adds five DB-backed integration tests that catch those failures at PR time.

What changed

• backend/device-register/main_integration_test.go (new): five integration tests under //go:build integration, each wrapped in _testdb.WithTx for rollback isolation.
  • TestDeviceRegisterHappyPath_InsertsRow — full payload insert, asserts all fields written.
  • TestDeviceRegisterUpsert_SameTokenUpdates — seeds a row then re-POSTs; asserts exactly one row with updated topic_ids.
  • TestDeviceRegisterMissingToken_Returns400 — empty JSON body; asserts 400 with "token" in error message.
  • TestDeviceRegisterMalformedJSON_Returns400 — non-JSON body; asserts 400 and zero rows written.
  • TestDeviceRegisterEmptyFollows_StoresEmptyArrays — omitted arrays; asserts non-NULL {} stored, not NULL.
• backend/device-register/go.mod: added epac/_testdb v0.0.0 require + replace directive (mirrors pattern in live-status/go.mod).

Trade-offs not taken

• Did not use t.Parallel() — the harness shares one migrated schema and sync.Once; parallel tests would race on migrated.Do. Sequential is consistent with all other integration tests in the repo.
• Did not assert granularity JSONB readback — the AC does not require it and the column defaults to {}. The core correctness (array types, upsert) is what matters here.

Test plan

# Requires Docker
cd backend
docker compose -f docker-compose.test.yml up -d
cd device-register
DATABASE_URL=postgres://epac:epac@localhost:5433/epac_test go test -tags=integration -v ./...
docker compose -f ../docker-compose.test.yml down

CI runs this automatically via the backend-integration-tests workflow.

Verification

• go build ./... — clean
• go vet -tags=integration ./... — clean
• Integration tests require a live Postgres instance (DATABASE_URL); skipped locally without Docker but run in CI.

Resolves EPAC-1875

Reviewer-Boundary: review-only

[riddim-developer-bot]

CI fix pushed — commit 4d7ad282

The test-integration job failed on TestSearchSpeechesLegacyFallback in backend/search/ (not in the device-register tests, which all passed: ok epac/device-register 0.740s).

Root cause (pre-existing on main — 4 consecutive failures before this PR opened):
TestSearchSpeechesLegacyFallback used defer conn.Close(ctx) which fired when the test function returned, closing the connection before the t.Cleanup(restoreSpeechVectors) callback could run — causing "conn closed". testdb.Connect already owns connection teardown via its own t.Cleanup, making the defer redundant and harmful.

Fix: removed the redundant defer conn.Close(ctx) from TestSearchSpeechesLegacyFallback only (the other search tests don't have t.Cleanup callbacks that use the connection, so their defer pattern is harmless). This restores the correct LIFO cleanup order: restoreSpeechVectors runs first, then conn.Close.

No production code changed. Device-register integration tests are unaffected.

[riddim-reviewer-bot]

⚠️ Autonomous review liveness watchdog

Symphony expected a reviewer-bot review for the current autonomous PR head within the configured SLA window, but none was found.

• PR: [EPAC-1875]: Add integration tests for POST /api/v1/device/register handler #459
• Repo: RiddimSoftware/epac
• Head SHA: 4d7ad282cd7dae8cf52682a1220f003364de8a27
• Suspected missing reviewer owner: RiddimSoftware/epac
• Review SLA window: 300000 ms
• PR last activity: 2026-05-14T23:47:16Z
• Last heartbeat: fresh at 2026-05-14T23:55:02Z from riddim1.local @ cb6c3f15b8d8a5b678830e54834e31b105a02632

[riddim-reviewer-bot]

ReviewAutonomousPR

• Verdict: approve
• Reviewer boundary: review_only
• Acceptance criteria coverage: covered=5, missing=0, unclear=0

Summary

The patch adds the requested DB-backed integration tests for POST /api/v1/device/register, including upsert and malformed-input behavior, and uses the shared integration harness correctly; overall it satisfies the acceptance criteria and is mergeable.

Actionable findings

1. risk / follow_up — Malformed-JSON no-write assertion is table-scoped instead of token-scoped (backend/device-register/main_integration_test.go:173)
   • TestDeviceRegisterMalformedJSON_Returns400 asserts COUNT(*) FROM device_subscriptions == 0 after sending invalid JSON. This is broader than necessary and can yield brittle failures if other fixture/test rows are present in the same shared table state. A token-specific absence check is safer and still verifies the contract.
   • Actionability: follow_up

Acceptance criteria coverage

• covered — TestDeviceRegisterHappyPath_InsertsRow
  • Implemented integration test posts valid payload, expects 200, reads back device_subscriptions, and validates stored token/member/topics/bills.
  • Actionability: none
  • Evidence: backend/device-register/main_integration_test.go
• covered — TestDeviceRegisterUpsert_SameTokenUpdates
  • Implemented by seeding a row for a token, posting again with the same token, asserting single-row count and updated topic_ids.
  • Actionability: none
  • Evidence: backend/device-register/main_integration_test.go
• covered — TestDeviceRegisterMissingToken_Returns400
  • Implemented with {} payload and asserts HTTP 400 plus error text containing token.
  • Actionability: none
  • Evidence: backend/device-register/main_integration_test.go
• covered — TestDeviceRegisterMalformedJSON_Returns400
  • Implemented malformed JSON path and checks for HTTP 400 and no writes, with an assertion that is currently table-wide rather than token-scoped.
  • Actionability: follow_up
  • Evidence: backend/device-register/main_integration_test.go
  • Suggested follow-up: Scope no-write assertion to test token or fixture isolation
• covered — TestDeviceRegisterEmptyFollows_StoresEmptyArrays
  • Implemented with missing topic_ids/bill_ids, asserts stored arrays are non-nil and length zero.
  • Actionability: none
  • Evidence: backend/device-register/main_integration_test.go