testing▌

Playwright E2E testing patterns with Page Object Model, configuration, CI/CD setup, and flaky test strategies. \n \n Provides Page Object Model structure for maintainable test organization, with reusable page classes that encapsulate locators and navigation logic \n Covers multi-browser testing across Chromium, Firefox, WebKit, and mobile devices with configurable retries, parallelization, and artifact capture (screenshots, videos, traces) \n Includes flaky test identification and remediation pa

Iterative test-debug-fix cycles for Airflow DAGs with comprehensive failure diagnosis. \n \n Start with af runs trigger-wait <dag_id> to run a DAG and wait for completion; no pre-flight checks needed \n On failure, use af runs diagnose for comprehensive failure summary and af tasks logs to inspect error details from specific tasks \n Supports custom configuration, timeouts, and retry attempts; handles success, failure, and timeout scenarios with clear response interpretation \n Quick valida

Browser automation and testing toolkit for local web applications using Playwright. \n \n Supports core browser interactions including navigation, form filling, clicking, dropdown selection, and dialog handling \n Includes verification capabilities for element presence, text content, visibility, URLs, and responsive design across viewports \n Provides debugging tools: screenshot capture, console log inspection, network request monitoring, and error handling patterns \n Works with Node.js environ

E2E testing utilities for Clerk authentication flows in Playwright and Cypress. \n \n Supports both Playwright and Cypress frameworks with framework-specific setup patterns (globalSetup for Playwright, custom commands for Cypress) \n Provides clerkSetup() and setupClerkTestingToken() utilities to initialize test environments and bypass bot detection \n Includes storageState persistence to reuse authenticated sessions across tests, reducing test execution time \n Requires test API keys ( pk_test_

Mutation testing assesses test suite quality by introducing small changes (mutations) to source code and verifying that tests fail. If tests don't catch a mutation, it indicates gaps in test coverage or test quality. This technique helps identify weak or ineffective tests.

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Testing patterns with Pest: Arrange-Act-Assert, proper mocking, null drivers, declarative factories.

Comprehensive testing framework for shell scripts using Bats with patterns, fixtures, and CI/CD integration. \n \n Covers core Bats concepts including test syntax, assertion patterns for exit codes and output, and setup/teardown lifecycle management \n Provides mocking and stubbing strategies for external commands, functions, and environment variables to isolate units under test \n Includes fixture management patterns, error condition testing, and shell compatibility validation across bash, sh,

Developer guide for extending Playwright MCP tools and CLI commands. \n \n Add new MCP tools in packages/playwright/src/mcp/browser/tools/ , register in tools.ts , and define capabilities in config.d.ts \n CLI commands map to MCP tools; register new commands in packages/playwright/src/mcp/terminal/commands.ts and update help generator if adding a category \n Config options require updates across program.ts (CLI option), config.d.ts (definition), and config.ts (implementation and environment mapp

Backtest crypto and traditional trading strategies against historical market data. \n \n Includes 8 pre-built strategies (SMA, EMA, RSI, MACD, Bollinger Bands, Breakout, Mean Reversion, Momentum) with customizable parameters \n Calculates comprehensive performance metrics: Sharpe, Sortino, Calmar ratios, max drawdown, VaR, volatility, win rate, and profit factor \n Supports parameter grid search optimization to find best-performing configurations across strategy parameters \n Generates trade-by-