testing▌

Protocol-based dependency injection for testable Swift code with focused abstractions and Swift Testing. \n \n Define small, single-responsibility protocols for each external concern (file system, network, APIs) and provide default production implementations \n Create mock implementations with configurable error properties to test failure paths deterministically without real I/O \n Inject dependencies via default parameters so production code uses real implementations automatically while tests o

Comprehensive Vue.js testing guidance covering unit, component, and end-to-end testing strategies. \n \n Addresses 11 common testing challenges including async handling, composable testing, Pinia store setup, Suspense components, and Teleport queries \n Recommends Vitest for unit and component testing infrastructure, with Playwright as the preferred E2E framework \n Covers black-box component testing patterns to prevent brittle tests during refactoring, async/await patterns to eliminate race con

ln-520-test-planner

Modern unit testing with MSTest 3.x/4.x using current APIs and best practices. \n \n Covers test class structure, lifecycle management, and the AAA (Arrange-Act-Assert) pattern with sealed classes and constructor-based initialization \n Provides comprehensive assertion APIs including equality, null checks, exception testing (Throws/ThrowsExactly), collections, strings, comparisons, and type assertions \n Supports data-driven tests via DataRow and DynamicData with ValueTuple and TestDataRow for t

Modern C++ testing workflow using GoogleTest/GoogleMock with CMake/CTest integration. \n \n Covers unit and integration test design with TDD red-green-refactor loop, fixtures, mocks, and fakes for dependency isolation \n Includes CMake/CTest configuration with automatic test discovery via gtest_discover_tests() and filtering strategies \n Provides coverage setup for GCC (gcov/lcov) and Clang (llvm-cov), plus sanitizer configuration (ASan, UBSan, TSan) for memory and race detection \n Documents f

Custom Playwright scripts for any browser automation task, with auto-detected dev servers and visible browser execution. \n \n Auto-detects running localhost dev servers; writes test scripts to /tmp to avoid project clutter \n Supports responsive design testing, login flows, form filling, link validation, and screenshot capture across multiple viewports \n Includes helper utilities for safe clicks, typed input, cookie banner handling, and table data extraction \n Configurable custom HTTP headers

End-to-end testing patterns with Playwright for full-stack Python/React applications. \n \n Covers test structure, page object model, selector strategy (data-testid > role > label), and wait strategies for reliable cross-browser testing \n Includes auth state reuse to avoid repeated logins, test data management via API helpers, and debugging techniques for flaky tests \n Provides CI integration examples, fixture setup for authentication, and naming conventions for tests, pages, and locators \n S

Robust backtesting systems that avoid look-ahead bias, survivorship bias, and overfitting. \n \n Event-driven and vectorized backtester implementations with realistic transaction cost modeling, slippage, and commission handling \n Walk-forward optimization and Monte Carlo simulation for strategy robustness testing across multiple time windows \n Comprehensive performance metrics including Sharpe, Sortino, Calmar ratios, drawdown analysis, and win-rate calculations \n Point-in-time data handling,

End-to-end testing focused on real user behavior, minimal mocking, and avoiding component unit tests. \n \n Prioritizes E2E tests over unit tests; reserves unit tests for pure functions only \n Emphasizes accessible selectors (role-based, label-based) over CSS selectors and test IDs in E2E tests \n Recommends writing E2E tests instead of heavily mocked unit tests; suggests 3+ mocks as a signal to switch approaches \n Includes rules for test structure, selector strategy, and when to apply each te

Guidance for property-based testing across languages and smart contracts. \n \n Detects high-value PBT patterns automatically: serialization pairs, parsers, validators, normalization, data structures, algorithms, and smart contract state invariants \n Provides a property catalog with 10 core patterns (roundtrip, idempotence, invariant, commutativity, associativity, identity, inverse, oracle, easy-to-verify, no exception) ranked by strength \n Includes decision tree routing to language-specific r