Testing & QA

Migrate Enzyme tests to React Testing Library for React 18 upgrades with a complete API mapping and behavior-testing philosophy.

Migrate Pester v5 classic Should -Be assertion syntax to the new Pester v6 Should-* operators with a step-by-step mapping and behavioral gotchas.

Enforces bulk-safety rules, sharing model requirements, CRUD/FLS security, SOQL injection prevention, PNB test coverage, and modern Apex idioms for Salesforce development.

Provides best practices for writing JavaScript/TypeScript tests using Jest, including test structure, mocking strategies, async testing, snapshot testing, and React component testing.

Uses mutation testing to systematically identify gaps in test vector coverage for cryptographic algorithms, then generates new test vectors that close those gaps. Measures effectiveness by comparing mutation kill rates before and after.

Fuzz C/C++ projects with multi-core support using AFL++, a fork of AFL with better performance and advanced features.

Build custom fuzzers with a modular Rust library, supporting advanced mutation strategies, custom feedback mechanisms, and non-standard target architectures.

Fuzz Python code and C extensions with coverage guidance and AddressSanitizer support using a libFuzzer-based fuzzer.

Set up continuous fuzzing infrastructure for open-source projects using Google's OSS-Fuzz platform, including building and running fuzz harnesses locally and enrolling new projects.

Configures mewt or muton mutation testing campaigns — scopes targets, tunes timeouts, and optimizes long-running runs.

Coverage-guided fuzzer built into LLVM for C/C++ projects. Use for fuzzing C/C++ code that can be compiled with Clang.

Fuzz Rust projects with libFuzzer using cargo-fuzz, including harness writing, sanitizer integration, and coverage analysis.

Validate cryptographic implementations against known attacks and edge cases using Wycheproof test vectors.

Write effective fuzzing harnesses across languages to improve code coverage and find bugs in your system under test.

Creates custom Semgrep rules for detecting security vulnerabilities, bug patterns, and code patterns with proper testing and validation.

Measures code coverage during fuzzing to assess harness effectiveness and identify fuzzing blockers.

Patch code to bypass checksums, global state, and validation checks that block fuzzer progress, using conditional compilation for C/C++ and Rust.

Guides fuzzers with domain-specific tokens to reach deeper code paths in parsers, protocol handlers, and file format processors.

Provides guidance for property-based testing across multiple languages and smart contracts, helping detect patterns where PBT offers stronger coverage than example-based tests.

Build production-ready React Native and Expo apps with guidance on components, styling, animations, navigation, state management, forms, networking, performance, testing, and deployment.

Validate skill outputs against assertion manifests to detect regressions, enforce quality gates, and bootstrap starter manifests from historical runs.

Write and run smart contract tests with Foundry, covering unit, fuzz, fork, and invariant testing, with guidance on what to test and common LLM pitfalls.

Build discrete-event simulations of systems with processes, queues, resources, and time-based events using SimPy in Python.

Provides domain-specific best practices for Node.js development with TypeScript, covering type stripping, async patterns, error handling, streams, modules, testing, performance, caching, logging, and more.

Guides development of Fastify Node.js backend servers and REST APIs using TypeScript or JavaScript, covering routes, plugins, validation, error handling, authentication, testing, performance, logging, deployment, and more.

Write readable, maintainable code through disciplined naming, small functions, and clean error handling.

Safely change and test untested codebases using techniques from Feathers' 'Working Effectively with Legacy Code': seams, characterization tests, sprout/wrap, and dependency-breaking.

Sets up a reliable end-to-end test suite as a per-PR gate, with real flows, layered assertions, reusable auth helpers, and video evidence.

Build modern PHP applications with strict typing, PHPStan level 9, Laravel or Symfony, and enterprise patterns including DTOs, DI, and comprehensive testing.

Implements concurrent Go patterns using goroutines and channels, designs and builds microservices with gRPC or REST, optimizes Go application performance with pprof, and enforces idiomatic Go with generics, interfaces, and robust error handling.

Generates type-safe, async-first Python 3.11+ code with full type annotations, mypy strict mode, pytest test suites, and validation via black and ruff.

Optimizes Active Record queries, implements Turbo Frames and Streams, configures Action Cable, sets up Sidekiq workers, and writes RSpec test suites for Rails 7+ applications.

Scaffolds NestJS modules, controllers, services, DTOs, guards, and interceptors for enterprise-grade TypeScript backends, with built-in validation, authentication, and testing patterns.

Builds Vue 3 components, composables, and Vite projects using JavaScript with JSDoc type annotations instead of TypeScript.

Builds, configures, and debugs enterprise Java applications with Spring Boot 3.x, microservices, or reactive programming, including WebFlux endpoints, JPA optimization, and Spring Security with OAuth2/JWT.

Writes, debugs, and refactors JavaScript code using modern ES2023+ features, async/await patterns, ESM module systems, and Node.js APIs.