BMAD-METHOD/.claude/rules/vitest-unit-testing-cursorrules-prompt-file

Vitest Unit Testing Prompt

A specialized .cursorrules prompt for creating comprehensive unit tests using Vitest with TypeScript support.

What You Can Build

• Unit Test Suites: Focused tests for critical business logic and utility functions
• Mock-Based Testing: Tests that properly isolate code from external dependencies using vi.mock
• Data-Driven Tests: Tests that validate functionality across multiple data scenarios
• TypeScript Testing: Strongly-typed tests with proper interface definitions and type assertions
• Edge Case Coverage: Tests that handle edge cases like undefined values and type mismatches

Benefits

• Modern Testing Framework: Leverage Vitest's speed and compatibility with Vite projects
• ESM-First Approach: Support for ES modules with top-level await and dynamic imports
• Proper Dependency Isolation: Consistent mocking of dependencies before imports
• Complete TypeScript Support: Full type safety for tested functions and mocked dependencies
• Comprehensive Test Coverage: Focus on business logic with various data scenarios
• Maintainable Test Structure: Organized tests with clear arrange-act-assert patterns

Synopsis

This prompt helps developers create high-quality unit tests with Vitest that focus on critical functionality while ensuring proper mocking of dependencies, comprehensive data scenarios, and edge case coverage.

Overview of .cursorrules Prompt

The .cursorrules prompt guides developers in creating effective unit tests using Vitest with these key elements:

• TypeScript Detection: Automatically detects and adapts to TypeScript usage in the project
• Dependency Mocking: Guidelines for properly mocking dependencies before imports using vi.mock
• Best Practices: Eight essential practices for unit testing, including critical functionality focus, data scenarios, and edge cases
• Example Test Patterns: Provides detailed examples of unit tests in both JavaScript and TypeScript with proper structure
• Maintainable Approach: Focus on writing a limited number of high-value tests per file
• Test Organization: Structure tests using describe/it blocks with descriptive names
• AAA Pattern: Examples using the Arrange-Act-Assert pattern for clear test structure