Testing Claude Skills
3 543 testing skills from 425 authors. They run test suites, check accessibility and catch what broke. Half of them fit into 1 799 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 429 copies of these same skills sitting in other people's repositories — counted once here, not 429 times.
3 543 unique 425 authors 2 updated this month 331 from vendors
Use when implementing BGTaskScheduler, debugging background tasks that never run, understanding why tasks terminate early, or testing background execution - systematic task lifecycle management with proper registration, expiration handling, and Swift 6 cancellation patterns
Use when encountering dependency conflicts, CocoaPods/SPM resolution failures, "Multiple commands produce" errors, or framework version mismatches - systematic dependency and build configuration debugging for iOS projects. Includes pressure scenario guidance for resisting quick fixes under time constraints
Use when debugging schema migration crashes, concurrency thread-confinement errors, N+1 query performance, SwiftData to Core Data bridging, or testing migrations without data loss - systematic Core Data diagnostics with safety-first migration patterns
Use when adding debug-only deep links for testing, enabling simulator navigation to specific screens, or integrating with automated testing workflows - enables closed-loop debugging without production deep link implementation
Use when implementing in-app purchases, StoreKit 2, subscriptions, or transaction handling - testing-first workflow with .storekit configuration, StoreManager architecture, transaction verification, subscription management, and restore purchases for consumables, non-consumables, and auto-renewable subscriptions
Use when ANY iOS build fails, test crashes, Xcode misbehaves, or environment issue occurs before debugging code. Covers build failures, compilation errors, dependency conflicts, simulator problems, environment-first diagnostics.
Use when writing ANY test, debugging flaky tests, making tests faster, or asking about Swift Testing vs XCTest. Covers unit tests, UI tests, fast tests without simulator, async testing, test architecture.
Use when ANY Metal porting issue occurs - black screen, rendering artifacts, shader errors, wrong colors, performance regressions, GPU crashes
Use when implementing passkey sign-in, replacing passwords with WebAuthn, configuring ASAuthorizationController, setting up AutoFill-assisted requests, adding automatic passkey upgrades, or migrating from password-based authentication. Covers passkey creation, assertion, cross-device sign-in, credential managers, and the Passwords app.
Use when writing unit tests, adopting Swift Testing framework, making tests run faster without simulator, architecting code for testability, testing async code reliably, or migrating from XCTest - covers @Test/@Suite macros, #expect/#require, parameterized tests, traits, tags, parallel execution, host-less testing
Use when SwiftData migrations crash, fail to preserve relationships, lose data, or work in simulator but fail on device - systematic diagnostics for schema version mismatches, relationship errors, and migration testing gaps
Use when creating SwiftData custom schema migrations with VersionedSchema and SchemaMigrationPlan - property type changes, relationship preservation (one-to-many, many-to-many), the willMigrate/didMigrate limitation, two-stage migration patterns, and testing migrations on real devices
Use when SwiftUI view debugging requires systematic investigation - view updates not working after basic troubleshooting, intermittent UI issues, complex state dependencies, or when Self._printChanges() shows unexpected update patterns - systematic diagnostic workflows with Instruments integration
Use when debugging SwiftUI view updates, preview crashes, or layout issues - diagnostic decision trees to identify root causes quickly and avoid misdiagnosis under pressure
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)