Unit Testing

Expert test automation engineer specializing in building robust test frameworks, CI/CD integration, and comprehensive test coverage. Masters multiple automation tools and frameworks with focus on maintainable, scalable, and efficient automated testing solutions.

Production-grade blockchain and Web3 development with Solidity (Ethereum/EVM), Rust (Solana), CosmWasm (Cosmos), including smart contract architecture, security patterns, gas optimization, testing strategies, DeFi protocols, and deployment workflows.

End-to-end web application testing with Playwright 1.57. Write and run browser automation tests from natural language, implement page object models, handle authentication, test responsive designs, and integrate with CI/CD pipelines. Includes Playwright Agents for AI-assisted test generation and Chrome for Testing builds.

Expert QA engineer specializing in comprehensive quality assurance, test strategy, and quality metrics. Masters manual and automated testing, test planning, and quality processes with focus on delivering high-quality software through systematic testing.

Production-grade frontend development with Next.js 16 App Router, TypeScript 5.9+ strict mode, Tailwind CSS v4, shadcn/ui, React 19.2 Server Components, state management (Zustand/Recoil), performance optimization (Turbopack stable, ISR/SSR/SSG), and accessibility best practices. Includes TanStack Query for server-state, Vitest for testing, and modern React patterns.

Use when building system provisioning manifests, handling multi-OS setups, managing package manager conflicts, or designing team provisioning workflows - provides patterns and safety procedures for declarative system configuration; emphasizes validation, dry-run testing, and staged rollout to prevent broken user setups

Expert risk manager specializing in comprehensive risk assessment, mitigation strategies, and compliance frameworks. Masters risk modeling, stress testing, and regulatory compliance with focus on protecting organizations from financial, operational, and strategic risks.

Test strategy, QA patterns, and automation practices across unit, integration, E2E, performance, BDD, and security testing with modern frameworks (Jest, Vitest, Playwright, k6, Cucumber).

Use when building e2e tests with Playwright, under deadline pressure to ship incomplete coverage, or struggling with wait strategies and mock-vs-reality tradeoffs - provides patterns for edge case coverage, deterministic waits, and strategic mocking decisions

Expert chaos engineer specializing in controlled failure injection, resilience testing, and building antifragile systems. Masters chaos experiments, game day planning, and continuous resilience improvement with focus on learning from failure.

Expert accessibility tester specializing in WCAG compliance, inclusive design, and universal access. Masters screen reader compatibility, keyboard navigation, and assistive technology integration with focus on creating barrier-free digital experiences.

Expert Site Reliability Engineer balancing feature velocity with system stability through SLOs, automation, and operational excellence. Masters reliability engineering, chaos testing, and toil reduction with focus on building resilient, self-healing systems.

Reusable QA harness for testing LLM agents and personas. Defines test suites with must-ace tasks, refusal edge cases, scoring rubrics, and regression protocols. Use when validating agent behavior, testing prompts after changes, or establishing quality baselines.

iOS app building and testing automation using Xcode simulator. Build, run, test iOS apps, capture screenshots, automate UI testing with XCTest, and integrate with Claude Code for mobile development workflows on macOS.

Expert refactoring specialist mastering safe code transformation techniques and design pattern application. Specializes in improving code structure, reducing complexity, and enhancing maintainability while preserving behavior with focus on systematic, test-driven refactoring.

Technical writing patterns for README files, API documentation, architecture decision records (ADRs), changelogs, contributing guides, code comments, and docs-as-code workflows. Covers documentation structure, style guides, Markdown best practices, and documentation testing.

Systematic research methodology for building comprehensive, current knowledge on any topic. Requires web_search tool. Use when questions require thorough investigation, recent developments post-cutoff, synthesis across multiple sources, or when Claude's knowledge may be outdated or incomplete. Triggered by "Research", "Investigate", "What's current on", "Latest info on", complex queries needing validation, or technical topics with recent changes.

Guide Test-Driven Development using Kent Beck's Red-Green-Refactor cycle. Use when writing tests, implementing features via TDD, or following plan.md test instructions.

Runs quality gate checks before commit or push. Executes lint fixes, TypeScript compilation, tests, and CI validation. Reproduces CI failures locally. Triggers on: pre-commit, pre-push, quality check, CI check, lint check, type check, validate changes, check:fix, pnpm test.

Run test coverage analysis, identify missed and partial lines, and write tests to improve coverage. Use this when the user asks to check coverage, improve coverage, or write tests for uncovered code. This skill detects both completely missed lines and partially covered lines (executed but missing branch coverage) to match Codecov analysis.