Unit Testing

JavaScript ES2024+ development specialist covering Bun runtime, Hono web framework, modern testing, linting (Biome), and edge-first development. Use when developing JavaScript APIs, web applications, or server-side projects.

Review checkpoint specs and tests to identify tests that encode ambiguous interpretations rather than explicit requirements. Use when asked to check checkpoint_N.md against test_checkpoint_N.py, when auditing tests for ambiguity, or when reviewing snapshot eval failures for interpretive issues.

Build and test this repo with the CMake preset debug-asan (AddressSanitizer). Use when asked how to configure, build, run, or test with ASAN/debug builds in this project.

Universal code patterns and best practices for dx-toolkit (Bun APIs, testing, error handling, type guards)

Fuzzing strategist persona specializing in dynamic testing guidance, fuzzing strategy development, and crash analysis

Run problem tests using eval-snapshot instead of raw pytest. Use this to evaluate solutions against benchmark tests in Docker. Invoke with /run-tests <snapshot_path> <problem_name> <checkpoint_index>.

Use when writing tests, debugging test failures, mocking dependencies, or using fake timers. Covers Vitest patterns, mock factories, and promise rejection handling.

Expert for developing Streamlit data apps for Keboola deployment. Activates when building, modifying, or debugging Keboola data apps, Streamlit dashboards, adding filters, creating pages, or fixing data app issues. Validates data structures using Keboola MCP before writing code, tests implementations with Playwright browser automation, and follows SQL-first architecture patterns.

Build and test Solidity smart contracts with Foundry toolkit. Use when developing Ethereum contracts, writing Forge tests, deploying with scripts, or debugging with Cast/Anvil. Triggers on Foundry commands (forge, cast, anvil), Solidity testing, smart contract development, or files like foundry.toml, *.t.sol, *.s.sol.

Patch engineer persona focused on security fix quality, code correctness, testing strategies, and regression prevention

Browser automation via Puppeteer CLI scripts (JSON output). Capabilities: screenshots, PDF generation, web scraping, form automation, network monitoring, performance profiling, JavaScript debugging, headless browsing. Actions: screenshot, scrape, automate, test, profile, monitor, debug browser. Keywords: Puppeteer, headless Chrome, screenshot, PDF, web scraping, form fill, click, navigate, network traffic, performance audit, Lighthouse, console logs, DOM manipulation, element selector, wait, scroll, automation script. Use when: taking screenshots, generating PDFs from web, scraping websites, automating form submissions, monitoring network requests, profiling page performance, debugging JavaScript, testing web UIs.

Test-Driven Development combined with emergent playtesting for Quest Keeper AI. Use when running playtest sessions, writing tests, debugging game feel issues, or following the RED-GREEN-REFACTOR cycle.

Build Solana programs with Anchor framework or native Rust. Use when developing Solana smart contracts, implementing token operations, testing programs, deploying to networks, or working with Solana development. Covers both high-level Anchor framework (recommended) and low-level native Rust for advanced use cases.

Systematic code refactoring following Martin Fowler's catalog. Methodologies: characterization tests, Red-Green-Refactor, incremental transformation. Capabilities: SOLID compliance, DRY cleanup, code smell detection, complexity reduction, legacy modernization, design patterns, functional programming patterns. Actions: refactor, extract, inline, rename, move, simplify code. Keywords: refactor, SOLID, DRY, code smell, complexity, extract method, inline, rename, move, clean code, technical debt, legacy code, design pattern, characterization test, Red-Green-Refactor, functional programming, higher-order function, immutability, pure function, composition, currying, side effects. Use when: improving code quality, reducing technical debt, applying SOLID principles, fixing DRY violations, removing code smells, modernizing legacy code, applying design patterns.

RSpec testing patterns, factories, mocks, and test best practices

Systematic debugging methodology with root cause analysis. Phases: investigate, hypothesize, validate, verify. Capabilities: backward call stack tracing, multi-layer validation, verification protocols, symptom analysis, regression prevention. Actions: debug, investigate, trace, analyze, validate, verify bugs. Keywords: debugging, root cause, bug fix, stack trace, error investigation, test failure, exception handling, breakpoint, logging, reproduce, isolate, regression, call stack, symptom vs cause, hypothesis testing, validation, verification protocol. Use when: encountering bugs, analyzing test failures, tracing unexpected behavior, investigating performance issues, preventing regressions, validating fixes before completion claims.

Analyze checkpoint tests and suggest missing edge cases. Use after writing tests or when reviewing test coverage. Invoke with /edge-cases <problem> <checkpoint>.

Cross-platform and native mobile development. Frameworks: React Native, Flutter, Swift/SwiftUI, Kotlin/Jetpack Compose. Capabilities: mobile UI, offline-first architecture, push notifications, deep linking, biometrics, app store deployment. Actions: build, create, implement, optimize, test, deploy mobile apps. Keywords: iOS, Android, React Native, Flutter, Swift, Kotlin, mobile app, offline sync, push notification, deep link, biometric auth, App Store, Play Store, iOS HIG, Material Design, battery optimization, memory management, mobile performance. Use when: building mobile apps, implementing mobile-first UX, choosing native vs cross-platform, optimizing battery/memory/network, deploying to app stores, handling mobile-specific features.

Claude Code extensibility: agents, skills, output styles. Capabilities: create/update/delete agents and skills, YAML frontmatter, system prompts, tool/model selection, resumable agents, CLI-defined agents. Actions: create, edit, delete, optimize, test extensions. Keywords: agent, skill, output-style, SKILL.md, subagent, Task tool, progressive disclosure. Use when: creating agents/skills, editing extensions, configuring tool access, choosing models, testing activation.

This skill should be used when writing, reviewing, or improving RSpec tests for Ruby on Rails applications. Use this skill for all testing tasks including model specs, controller specs, system specs, component specs, service specs, and integration tests. The skill provides comprehensive RSpec best practices from Better Specs and thoughtbot guides.