Test Helper Skill

Instructions

When working with tests in this project:

1. •

   Running Tests

   • •Unit tests: pnpm test:run (Vitest)
   • •Watch mode: pnpm test
   • •Coverage: pnpm test:coverage
   • •E2E tests: pnpm test:e2e (requires dev server running)
2. •

   Test File Locations

   • •Unit tests: Colocated with source files (*.test.ts)
   • •E2E tests: tests/e2e/
   • •Security tests: tests/security/
3. •

   Financial Engine Tests

   • •Located in src/lib/engine/
   • •Target 100% coverage for engine code
   • •Use golden models in validation/golden-models/ for regression testing
4. •

   Writing New Tests

   • •Always use Decimal.js for financial assertions
   • •Compare Decimals with .equals() or .toNumber() for approximate comparisons
   • •Include edge cases for all three rent models
   • •Test all three periods (historical, transition, dynamic)
5. •

   Debugging Failures

   • •Check for floating-point precision issues (use Decimal.js)
   • •Verify test data matches expected period calculations
   • •Review golden model files for expected outputs
6. •

   Negotiation Tests (v2.2)

   • •Test negotiation CRUD operations at /api/negotiations
   • •Verify counter-offer creation and linking
   • •Test status transitions (ACTIVE → ACCEPTED/REJECTED/CLOSED)
   • •Validate timeline reordering logic
   • •Ensure developer + property uniqueness constraint

Common Test Patterns

import Decimal from 'decimal.js';
import { describe, it, expect } from 'vitest';

describe('Financial Calculation', () => {
  it('should calculate rent correctly', () => {
    const result = calculateRent(input);
    expect(result.rent.equals(new Decimal('1000000'))).toBe(true);
  });
});

Examples

• •"Run the financial engine tests"
• •"Debug why this test is failing"
• •"Write tests for the new rent calculation"
• •"Test the negotiation workflow" (v2.2)
• •"Verify counter-offer creation" (v2.2)