Plan an enterprise connector migration with compatibility tests

A connector migration is a contract change even when the vendor says the new endpoint is compatible. Authentication, pagination, ordering, null handling, rate limits and error semantics can shift independently of the happy-path schema.

Build the decision artifact

Freeze golden request and response fixtures from approved synthetic or sanitized shapes. Run old and new readers in shadow, normalize irrelevant differences and classify every material mismatch. Keep one write authority until reads agree, rehearse rollback, then canary writes with idempotency and reconciliation.

The enterprise delivery lab makes this reasoning executable with synthetic data:

from enterprise_cases import connector_migration_case

result = connector_migration_case()
assert result["fixtures"] == 3
assert result["mismatches"] == []
assert result["shadow_reads"] is True
assert result["write_path"] == "old"

The fixture compares three records with no mismatch while retaining the old connector as the write path. That ordering matters: parity evidence precedes cutover. A zero-mismatch sample is evidence about these fixtures only, not proof of universal compatibility.

Test the failure path

Byte-for-byte comparison can flag harmless ordering while missing semantic changes such as a timezone or omitted default. Define equivalence at the domain layer. Also test throttling, expired credentials, partial pages, duplicated webhooks and the rollback path after the new connector has written data.

Save evidence that another reviewer can inspect:

• versioned golden fixtures
• normalization and semantic-equivalence rules
• shadow mismatch report
• cutover, reconciliation and rollback runbook

This exercise aligns with the enterprise delivery, secure integration, operations and leadership work in the FDE for Professionals course. The course link describes the pathway; this local draft and its synthetic verifier do not claim that a client deployment, security approval or production result occurred.

Practice task

Create an old/new fixture pair with one harmless and one material difference. Make the comparator ignore the first and block on the second.

Continue learning

This article is part of the Enterprise AI delivery and architecture sequence. Use the neighbouring tasks when you need the prerequisite or the next application.

• Review the prerequisite or neighbouring task in Integrate a legacy system through a typed adapter.
• Continue with Build a durable workflow for a multi-day business process.

Reference: Pact contract testing documentation.