We establish fast, isolated unit tests with clear boundaries, mocks, and fakes. Coverage thresholds protect critical logic, while naming, structure, and fixtures keep suites readable and maintainable for new contributors and reviewers across the codebase.

We validate real interactions across modules, databases, caches, queues, and APIs. Contract tests prevent breaking changes between services, enabling independent releases and safer refactors without cross-team coordination debt or customer-facing regressions.

We curate regression suites by risk and usage, tagging scenarios for smoke, sanity, and full runs. Impact analysis prioritizes tests after code changes, keeping pipelines fast while guarding revenue-critical workflows and compliance-sensitive logic.

Factories, seeders, and anonymization produce stable, realistic data across environments. Ephemeral test DBs, containers, and queues isolate state and reduce flakiness, enabling confident, reproducible results in CI.

Pipelines run tiered suites with caching, sharding, and parallelization. Gates enforce coverage, lint, type checks, and performance budgets. Fast feedback preserves developer momentum while blocking risky merges from reaching main.

We refactor brittle tests, remove duplication, and coach teams on design-for-testability. Playbooks, templates, and patterns keep quality sustainable as systems and squads scale.