Testing Skills

Use when building Typer/Rich CLI applications or reviewing existing CLI code for correctness. Activates on requests involving Rich table rendering, console output handling, testing Rich-formatted output, or Typer command wiring. Prevents common AI mistakes — Rich table wrapping in non-TTY contexts, incorrect stderr/stdout separation, and integration pitfalls. Load alongside the typer and rich API reference skills.

Use when building CLI applications with Typer — creating commands, defining arguments and options, composing subcommands, testing with CliRunner, or using advanced features like callbacks and autocompletion. Covers app creation, parameter types, subcommand composition, testing patterns, and output utilities.

Use when debugging software, investigating incidents, diagnosing flaky tests, or analyzing performance regressions — enforces structured observation recording with evidence IDs, causality validation, and verification gates to prevent correlation-causation pollution. Use when an agent might otherwise summarize or speculate instead of reporting observed evidence.

| Building robust R packages with modern tidyverse patterns. Use this skill when creating or maintaining R packages, designing APIs, choosing dependencies, implementing input validation, writing error messages, or deciding between internal and exported functions. Covers dependency strategy, tidyverse API design patterns, validation approaches, error handling with cli/rlang, testing levels, and documentation priorities.

| Type-stable vector operations and custom vector classes using vctrs. Use this skill when building R packages with custom types, need guaranteed output types regardless of input values, implementing consistent coercion/casting rules, or creating vector classes that work seamlessly with data frames. Covers when to use vctrs vs base R, building custom vector classes, coercion methods, and testing vctrs classes.

Use when diagnosing and fixing bugs in a Kotlin Multiplatform project. Focus on root-cause analysis, minimal safe fixes, KMP correctness, UI/state/data/persistence/concurrency issues, and regression prevention.

Use when designing, implementing, or reviewing tests in KMP projects — unit tests, instrumented tests, Compose Multiplatform UI tests, test doubles, test strategy, stability, performance, and screenshot testing.

Perform mutation testing on the codebase. Introduces deliberate bugs one at a time, checks whether the test suite catches each one, and reports on test suite gaps. Optionally implements missing tests.

Use when validating the Mathodology skills-only repository or preserving archived knowledge about the former development, testing, deployment, packaging, and release workflows.

Use when running Mathodology award-workflow phase gates, judge panels, structured handoffs, figure QA, or rendered-PDF QA in a contest run.

Laravel 13 queue and job patterns — driver choice, job design (idempotency, ShouldQueue, model serialisation), retry and failure handling, worker scaling, Bus batching and chaining, Horizon when warranted, queue testing. Use when designing async jobs, scheduling background work, configuring Horizon, debugging stuck jobs, or auditing queue health. Triggers on "Laravel queue", "Laravel job", "background job", "Horizon setup", "failed jobs", "Bus batch", "queue worker tuning".

End-to-end testing with Playwright for web applications. Use when writing E2E tests, browser automation, form submission testing, or user flow testing. Triggers on "playwright", "e2e test", "browser test", "end-to-end", "form flow testing", or test files in tests/e2e/.

Laravel 13 testing with Pest PHP 4 or PHPUnit 12. Use when writing feature tests, unit tests, or any test code in a Laravel application. Triggers on tasks involving HTTP tests, model factories, database assertions, mocking facades, authentication testing, or test organisation patterns.

Unit testing, integration testing, and test-driven development principles. Use when writing tests, reviewing test code, improving test coverage, or setting up testing strategy. Triggers on "write tests", "review tests", "testing best practices", or "TDD".

Host-based simulation using the Zephyr native_sim board. Covers building for Linux/macOS/Windows, automated testing, host-side debugging (GDB, Valgrind), and host-target integration. Trigger when developing application logic without hardware or setting up CI/CD tests.

Testing and debugging for Zephyr RTOS. Covers the Ztest framework for unit and integration tests, the Twister test runner for automated HIL/SIM validation, and advanced tracing/debugging techniques (SystemView, Thread Analyzer, Stack analysis). Trigger when writing unit tests, setting up CI/CD pipelines, or analyzing system performance and latency.

Use when working a mission or slice: the SDLC flow (intent -> mini-requirements + proof contract -> mockups -> plan-lock -> build -> QA -> `rig proof` drops -> proof-lock), and how to track, prove, and hand off state across agents and compaction via PROGRESS.md / PROOF.md / MISSION_NOTES.md. Covers the two locks, role contracts, hot-potato queue handoff, and the `rig scope audit` backstop.

Create UI mockups at three fidelity levels — ASCII wireframes for quick iteration, standalone HTML mockups for delivery with requirements, and live prototypes for interaction testing.

How the development pod coordinates implementation, QA, and design without skipping gates.

Systematically explore and test a web application to find bugs, UX issues, and other problems. Use when asked to "dogfood", "QA", "exploratory test", "find issues", "bug hunt", "test this app/site/platform", or review the quality of a web application. Produces a structured report with full reproduction evidence -- step-by-step screenshots, repro videos, and detailed repro steps for every issue -- so findings can be handed directly to the responsible teams.

Use when about to claim work is complete, fixed, or passing, before committing or creating PRs - requires running verification commands and confirming output before making any success claims; evidence before assertions always

Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes

[AUTO-INVOKE] MUST be invoked BEFORE writing or modifying any test files (*.t.sol). Covers test structure, naming conventions, coverage requirements, fuzz testing, and Foundry cheatcodes. Trigger: any task involving creating, editing, or running Solidity tests.

Patterns for building entity actors with Akka.Hosting - GenericChildPerEntityParent, message extractors, cluster sharding abstraction, akka-reminders, and ITimeProvider. Supports both local testing and clustered production modes.

Write unit and integration tests for Akka.NET actors using modern Akka.Hosting.TestKit patterns. Covers dependency injection, TestProbes, persistence testing, and actor interaction verification. Includes guidance on when to use traditional TestKit.

Write integration tests using .NET Aspire's testing facilities with xUnit. Covers test fixtures, distributed application setup, endpoint discovery, and patterns for testing ASP.NET Core apps with real dependencies.

Write UI tests for Blazor applications (Server or WebAssembly) using Playwright. Covers navigation, interaction, authentication, selectors, and common Blazor-specific patterns.

Use Verify for snapshot testing in .NET. Approve API surfaces, HTTP responses, rendered emails, and serialized outputs. Detect unintended changes through human-reviewed baseline files.

Write integration tests using TestContainers for .NET with xUnit. Covers infrastructure testing with real databases, message queues, and caches in Docker containers instead of mocks.

Snapshot test email templates using Verify to catch regressions. Validates rendered HTML output matches approved baseline. Works with MJML templates and any email renderer.

Expert guidance for Swift Testing: test structure, #expect/#require macros, traits and tags, parameterized tests, test plans, parallel execution, async waiting patterns, and XCTest migration. Use when writing new Swift tests, modernizing XCTest suites, debugging flaky tests, or improving test quality and maintainability in Apple-platform or Swift server projects.

End-to-end testing specialist using Playwright. Use PROACTIVELY for generating, maintaining, and running E2E tests. Manages test journeys, quarantines flaky tests, uploads artifacts (screenshots, videos, traces), and ensures critical user flows work.

Use this skill when writing new features, fixing bugs, or refactoring code. Enforces test-driven development with 80%+ coverage including unit, integration, and E2E tests.

Use when implementing app integrity verification, preventing fraud with DCAppAttestService, validating requests from legitimate app instances, using DeviceCheck for promotional abuse prevention, or needing server-side attestation/assertion validation. Covers key generation, attestation, assertion, rollout strategy, and risk metrics.

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