3 535 testing skills from 425 authors. They run test suites, check accessibility and catch what broke. Half of them fit into 1 800 tokens or less — that is what one costs your context window when the agent loads it. 404 ship runnable scripts rather than instructions alone. 2 of them cannot work without an MCP server, most often rube. We also found 403 copies of these same skills sitting in other people's repositories — counted once here, not 403 times.
3 535 unique 425 authors 2 157 updated this month 319 from vendors
Use when testing async code with Swift Testing. Covers confirmation for callbacks, @MainActor tests, async/await patterns, timeout control, XCTest migration, parallel test execution.
Use when writing UI tests, recording interactions, tests have race conditions, timing dependencies, inconsistent pass/fail behavior, or XCTest UI tests are flaky - covers Recording UI Automation (WWDC 2025), condition-based waiting, network conditioning, multi-factor testing, crash debugging, and accessibility-first testing patterns
Use when encountering BUILD FAILED, test crashes, simulator hangs, stale builds, zombie xcodebuild processes, "Unable to boot simulator", "No such module" after SPM changes, or mysterious test failures despite no code changes - systematic environment-first diagnostics for iOS/macOS projects
Use when writing, running, or debugging XCUITests. Covers element queries, waiting strategies, accessibility identifiers, test plans, and CI/CD test execution patterns.
Differential expression analysis for label-free quantitative (LFQ) intensity data with standard MaxQuant and DIA-NN output. Workflow includes preprocessing, imputation, and statistical testing.
Differential expression analysis for bulk RNA-seq and pseudo-bulk count matrices with QC, PCA, and contrast testing.
Designs and implements testing strategies for any codebase. Use when adding tests, improving coverage, setting up testing infrastructure, debugging test failures, or when asked about unit tests, integration tests, or E2E testing.
Automate Test App tasks via Rube MCP (Composio). Always search tools first for current schemas.
Toolkit for interacting with and testing local web applications using Playwright. Supports verifying frontend functionality, debugging UI behavior, capturing browser screenshots, and viewing browser logs.
When the user wants to A/B test App Store product page elements to improve conversion rate. Also use when the user mentions "A/B test", "product page optimization", "test my screenshots", "test my icon", "conversion rate optimization", "CPP", or "custom product pages". For screenshot design, see screenshot-optimization. For metadata optimization, see metadata-optimization.
When the user wants to design, optimize, or evaluate App Store screenshots and preview videos. Also use when the user mentions "screenshots", "app preview", "product page design", "screenshot design", "creative assets", or "what should my screenshots show". For A/B testing screenshots, see ab-test-store-listing. For full ASO audit, see aso-audit.
Set up doctest testing framework in CMake C++ projects and write tests colocated with implementation code
> Core catalog of 8 critical Elixir/Phoenix anti-patterns covering error handling, separation of concerns, Ecto queries, and testing.
> Playwright E2E testing patterns.
> Pytest testing patterns for Python.
Master C#/.NET backend development patterns for building robust APIs, MCP servers, and enterprise applications. Covers async/await, dependency injection, Entity Framework Core, Dapper, configuration, caching, and testing with xUnit. Use when developing .NET backends, reviewing C# code, or designing API architectures.
Master end-to-end testing with Playwright and Cypress to build reliable test suites that catch bugs, improve confidence, and enable fast deployment. Use when implementing E2E tests, debugging flaky tests, or establishing testing standards.
Golang CLI application development. Use when building, modifying, or reviewing a Go CLI tool — especially for command structure, flag handling, configuration layering, version embedding, exit codes, I/O patterns, signal handling, shell completion, argument validation, and CLI unit testing. Also triggers when code uses cobra, viper, or urfave/cli.
Provides gRPC usage guidelines, protobuf organization, and production-ready patterns for Golang microservices. Use when implementing, reviewing, or debugging gRPC servers/clients, writing proto files, setting up interceptors, handling gRPC errors with status codes, configuring TLS/mTLS, testing with bufconn, or working with streaming RPCs.
Comprehensive guide to stretchr/testify for Golang testing. Covers assert, require, mock, and suite packages in depth. Use whenever writing tests with testify, creating mocks, setting up test suites, or choosing between assert and require. Essential for testify assertions, mock expectations, argument matchers, call verification, suite lifecycle, and advanced patterns like Eventually, JSONEq, and custom matchers. Trigger on any Go test file importing testify.
Provides a comprehensive guide for writing production-ready Golang tests. Covers table-driven tests, test suites with testify, mocks, unit tests, integration tests, benchmarks, code coverage, parallel tests, fuzzing, fixtures, goroutine leak detection with goleak, snapshot testing, memory leaks, CI with GitHub Actions, and idiomatic naming conventions. Use this whenever writing tests, asking about testing patterns or setting up CI for Go projects. Essential for ANY test-related conversation in Go.
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. Use when setting up Node.js projects with native TypeScript support, configuring type stripping (--experimental-strip-types), writing Node 22+ TypeScript without a build step, or when the user mentions 'native TypeScript in Node', 'strip types', 'Node 22 TypeScript', '.ts files without compilation', 'ts-node alternative', or needs guidance on error handling, graceful shutdown, flaky tests, profiling, or environment configuration in Node.js. Helps configure tsconfig.json for type stripping, set up package.json scripts, handle module resolution and import extensions, and apply robust patterns across the full Node.js stack.
Implement comprehensive testing strategies with pytest, fixtures, mocking, and test-driven development. Use when writing Python tests, setting up test suites, or implementing testing best practices.
Standards for Unit Tests, UI Tests (Compose), and Hilt Integration. Use whenever writing Android test files or asking about runTest, composeTestRule, HiltAndroidRule, MockK, MainDispatcherRule, @TestInstallIn, or how to test a ViewModel/Composable/Repository in Android. (triggers: **/*Test.kt, **/*Rule.kt, @Test, runTest, composeTestRule, HiltAndroidTest, MockK, createAndroidComposeRule, MainDispatcherRule, @TestInstallIn)
Standards for Component Test Harnesses and TestBed. Use when writing Angular component tests with TestBed or Component Harnesses. (triggers: **/*.spec.ts, TestBed, ComponentFixture, TestHarness, provideHttpClientTesting)
Systematic troubleshooting using the Scientific Method. Use when debugging crashes, tracing errors, diagnosing unexpected behavior, or investigating exceptions. (triggers: debug, fix bug, crash, error, exception, troubleshooting)
Enforces Test-Driven Development (Red-Green-Refactor). Use when writing unit tests, implementing TDD, or improving test coverage for any feature. (triggers: **/*.test.ts, **/*.spec.ts, **/*_test.go, **/*Test.java, **/*_test.dart, **/*_spec.rb, tdd, unit test, write test, red green refactor, failing test, test coverage)
Systematic troubleshooting using the Scientific Method. Use when debugging crashes, tracing errors, diagnosing unexpected behavior, or investigating exceptions.
BLoC/Cubit state management standards. ALWAYS consult when writing, modifying, reviewing, or testing any BLoC, Cubit, state, or event Dart file — even for small changes. (triggers: **_bloc.dart, **_cubit.dart, **_state.dart, **_event.dart, BlocProvider, BlocBuilder, BlocListener, Cubit, Emitter)
Unit, widget, and integration testing with robots, widget keys, and Patrol. Use when writing Flutter unit tests, widget tests, or integration tests with Patrol. (triggers: **/test/**.dart, **/integration_test/**.dart, **/robots/**.dart, lib/core/keys/**.dart, test, patrol, robot, WidgetKeys, patrolTest, blocTest, mocktail)
Standards for unit testing, table-driven tests, and mocking in Golang. Use when writing Go unit tests, table-driven tests, or using mock interfaces. (triggers: **/*_test.go, testing, unit tests, go test, mocking, testify)
Testing standards using JUnit 5, AssertJ, and Mockito for Java. Use when writing or reviewing Java unit tests, setting up parameterized tests, writing integration tests with Testcontainers, or working with Mockito mocks. (triggers: **/*Test.java, **/*IT.java, @Test, @ParameterizedTest, Mockito, AssertJ, assertThat, JUnit, Testcontainers)
Development tools, linting, and testing for JavaScript projects. Use when configuring ESLint, Prettier, or test runners for JavaScript projects. (triggers: .eslintrc.*, jest.config.*, package.json, eslint, prettier, jest, test, lint, build)
Standards for Gradle Kotlin DSL, Version Catalogs, and MockK for Kotlin projects. Use when configuring build.gradle.kts, setting up libs.versions.toml, adding MockK for tests, or choosing between Kotlin-compatible test assertion libraries. (triggers: build.gradle.kts, libs.versions.toml, detekt.yml, mockk, kts, version catalog, kotest)
Automated testing standards with Pest and PHPUnit. Use when writing Pest or PHPUnit feature/unit tests in Laravel applications. (triggers: tests/**/*.php, phpunit.xml, feature, unit, mock, factory, sqlite)
Unit and E2E testing with Jest, mocking strategies, and database isolation. Use when writing NestJS unit tests, E2E tests with supertest, or mock providers. (triggers: **/*.spec.ts, test/**/*.e2e-spec.ts, Test.createTestingModule, supertest, jest, beforeEach)
Unit, Integration, and E2E testing standards for App Router. Use when writing unit, integration, or Playwright E2E tests for a Next.js App Router project. (triggers: **/*.test.{ts, tsx}, cypress/**, tests/**, vitest, playwright, msw, testing-library)
Unit and integration testing standards for PHP applications. Use when writing PHPUnit unit tests or integration tests for PHP applications. (triggers: tests/**/*.php, phpunit.xml, phpunit, pest, mock, assert, tdd)
Standards for maintaining code hygiene, automated checks, and testing integrity.
End-to-end Jira → Zephyr workflow: parse AC, identify platform and market, impact-analyze existing TCs (update vs create new), draft test cases with correct naming/metadata/preconditions, and link back via create_test_case_issue_link. Use when converting a Jira story into Zephyr TCs, or when requirement changes require updating existing TCs rather than creating duplicates. (triggers: **/user_story.md, generate test cases, zephyr, impact analysis, create test case)
Jest and React Native Testing Library for component and integration tests. Use when writing Jest or React Native Testing Library tests for React Native components. (triggers: **/*.test.tsx, **/*.spec.tsx, __tests__/**, test, testing, jest, render, fireEvent, waitFor)
Testing strategies with RTL and Jest/Vitest. Use when writing React component tests with React Testing Library, Jest, or Vitest. (triggers: **/*.test.tsx, **/*.spec.tsx, render, screen, userEvent, expect)
Standards for creating, testing, and optimizing Agent Skills. Use when creating, improving, catching regressions, measuring trigger rates, or writing eval cases for any skill.
Standards for unit, integration, and slice testing in Spring Boot 3. Use when writing unit tests, integration tests, or slice tests for Spring Boot 3 applications. (triggers: **/*Test.java, webmvctest, datajpatest, testcontainers, assertj)
Standards for XCTest, Async Tests, and Test Organization. Use when writing XCTest cases, async tests, or organizing test suites in Swift. (triggers: **/*Tests.swift, XCTestCase, XCTestExpectation, XCTAssert)
Enforces Test-Driven Development (Red-Green-Refactor). Use when writing unit tests, implementing TDD, or improving test coverage for any feature.
Development tools, linting, and build config for TypeScript. Use when configuring ESLint, Prettier, Jest, Vitest, tsconfig, or any TS build tooling.
Development tools, linting, and build config for TypeScript. Use when configuring ESLint, Prettier, Jest, Vitest, tsconfig, or any TS build tooling. (triggers: tsconfig.json, .eslintrc.*, jest.config.*, package.json, eslint, prettier, jest, vitest, build, compile, lint)