cashflow-testinglisted

# Cashflow Testing Guide ## Test Commands ```bash npm test # Run all tests once npm run test:watch # Run tests in watch mode npm run test:coverage # Run tests with coverage report ``` ## Test Structure - Tests are in `src/cashflow.test.js` - Uses Vitest as the test runner - All tests run in Node environment (no browser required) ## Test Coverage The test suite covers: 1. **runSimulation** - Main simulation function - Continuous daily entries from start to end - Balance calculation with cashflow accumulation - Multiple events on same day - Date range clipping 2. **Date Parsing** - YYYY-MM-DD format parsing (local time) - Date object pass-through - Invalid input handling 3. **Frequency Handling** - Daily, weekly, monthly, quarterly, semi-annual, annual - Month overflow (Jan 31 → Feb 28/29) - Leap year handling (Feb 29) 4. **Validation** - Valid date checking - Frequency validation with descriptive errors ## Adding Tests When adding features: 1. Add unit tests for new functions in `src/cashflow.test.js` 2. Test edge cases (boundary conditions, invalid inputs) 3. Ensure all 30 existing tests still pass 4. Run `npm run test:coverage` to verify coverage thresholds ## Coverage Thresholds - Statements: 80% - Branches: 80% - Functions: 80% - Lines: 80%