DLR Processor — Testing Strategy

Status: populated Owner: Platform Engineering Last updated: 2026-04-18 Companion: APPLICATION_LOGIC · FAILURE_MODES

1. Coverage Target

≥ 80% line coverage on all service-owned source files.

2. Unit Tests

Framework: Jest + ts-jest

Key Unit Test Cases

Module	Test Case
DlrStatusNormaliser	All 8 known SMPP stat values map correctly
DlrStatusNormaliser	Unknown stat maps to UNKNOWN
DlrStatusNormaliser	Case-insensitive input (delivrd → DELIVERED)
InboundDlrEventSchema	Valid payload passes validation
InboundDlrEventSchema	Missing operatorMessageId fails
InboundDlrEventSchema	deliveredAt not ISO-8601 fails
DeliveryReceiptRepository	Insert returns new receiptId
DeliveryReceiptRepository	Duplicate operatorMessageId returns null (conflict)
DlrProcessingService	Duplicate DLR short-circuits after idempotency check
DlrProcessingService	Orphan path writes to orphaned_receipts and publishes sms.dlr.unmatched
DlrProcessingService	Terminal status triggers billing + webhook outbox entries
DlrProcessingService	UNKNOWN status triggers webhook but not billing
OrchestratorUpdater	Does not overwrite already-terminal orch.sms_messages row

3. Integration Tests

Framework: Jest + Testcontainers (PostgreSQL 15, NATS JetStream)

Scenarios

Scenario	Steps
Happy path DELIVERED	Publish DLR event → assert delivery_receipts row, sms_messages update, outbox entries
Idempotent duplicate	Publish same DLR twice → assert single row in delivery_receipts
Orphan flow	Publish DLR with unknown operatorMessageId → assert orphaned_receipts row + sms.dlr.unmatched published
DB transaction rollback	Simulate NATS publish failure → assert no delivery_receipts row persisted
Consumer recovery	Stop NATS → reconnect → assert pending messages processed

4. End-to-End Tests

Scope: Full platform smoke test (separate e2e test suite in repo root).

DLR Processor participation:

• Send SMS via HTTP API → mock smpp-connector publishes DLR → assert orch.sms_messages.status = DELIVERED.
• Verify billing.events received by mock billing consumer.
• Verify webhook.dispatch received by mock webhook consumer.

5. Contract Tests

Tool: Pact (consumer-driven contract testing).

Contract	Consumer	Provider
sms.dlr.inbound schema	dlr-processor	smpp-connector
billing.events schema	billing-service	dlr-processor
webhook.dispatch schema	webhook-dispatcher	dlr-processor

Pact broker: internal Pact Broker instance. CI verifies contracts on every PR.

6. Performance Tests

Tool: k6 with NATS publisher scripts.

Target: 1 000 DLRs/second sustained for 60 seconds. Success criterion: p99 processing latency < 500 ms; error rate < 0.1%; no orphan leakage.

7. CI Pipeline

lint → unit tests → integration tests (Testcontainers) → contract tests → build image → trivy scan

E2E tests run post-deploy to staging environment.