Testing & QA

Write table-driven Go tests with subtests, benchmarks, fuzzing and coverage

Plan pytest suites with fixtures, mocks, parametrized tests and coverage targets

Practice TDD in Spring Boot with JUnit 5, Mockito, MockMvc and Testcontainers

Run Spring Boot build, lint, coverage and security checks before every release

Enforce test-driven development for features, fixes and refactors at 80% coverage

Verify Claude Code session changes with a repeatable, full checking loop

Debug hard issues with evidence gathering, hypothesis tests and root cause checks

Emulate Sign in with Apple and OIDC locally to test Apple sign-in

Emulate AWS S3, SQS, Cognito, IAM and STS locally for tests without a real account

Build and share emulators for third-party HTTP APIs that your tests depend on

Run local API emulators for GitHub, Google, Slack, Stripe and more in CI

Emulate the GitHub REST API locally to test repos, PRs, OAuth and webhooks

Emulate Google OAuth, OpenID Connect, Gmail, Calendar and Drive for local tests

Emulate the Linear GraphQL API locally to test issues, teams and webhooks

Emulate Microsoft Entra ID sign-in, OIDC and Graph /me for local tests

Embed API emulators in a Next.js app for same-origin OAuth on preview deployments

Embed API emulators in a Nuxt app for same-origin OAuth on preview deployments

Emulate the Resend email API locally to test sends, magic links and auth codes

Emulate the Slack Web API locally to test channels, messages and webhooks

Emulate Stripe payments, checkout, customers and webhooks locally without real charges

Emulate Twilio messaging, Verify, voice and webhooks in local tests

Emulate the Vercel REST API locally to test projects, deployments and env vars

Analyze evlog NDJSON logs to debug errors, slow requests and request patterns

Design mock API services that simulate real behavior for development and demos

Measure layout shift, theme flicker and page performance before and after fixes

Diagnose errors, failing tests and unexpected behavior in code

Diagnose failures with observability data, ranked hypotheses and targeted logging

Set up distributed tracing and debugging environments for dev and production

Analyze production errors and incidents with observability and root-cause methods

Search logs and code for error patterns and correlate failures to root causes

Analyze production errors and incidents with observability and root-cause methods

Diagnose failures with observability data, ranked hypotheses and targeted logging

Write LibFuzzer fuzz drivers and fuzz targets for Python libraries

Isolate root causes, make focused fixes and verify recovery with regression tests

Check output masks for format, value range and consistency before submission

Extract kernel constants for syzkaller syzlang syscall descriptions

Add new syscall descriptions to syzkaller with a full build and test loop

Learn syzlang syntax and write descriptions for ioctl syscalls

Build test automation strategies with self-healing tests and CI integration

Write and review Python tests with pytest fixtures, parametrization and mocks

Verify UI changes with screenshot analysis, visual regression and accessibility checks

Generate maintainable unit tests with strong coverage and edge case focus

Decide what to test and how with deterministic decision gates and test schemas

Systematically fix failing tests after business logic changes or refactoring

Trace a deep error back through the call stack to its original trigger

Assess test coverage quality with structural, mutation and requirements analysis

Write a failing test first, then the minimal code that makes it pass

Drill from a symptom to its root cause by asking why five times

Generate test files for uncommitted changes and fill in missing coverage