hotovo/writing-tests

Writing Tests

Write effective tests using Vitest and React Testing Library.

Quick Start

Create a unit test in packages/common/__tests__/utils/math.test.ts:

import { describe, it, expect } from 'vitest';
import { add } from '../../utils/math';

describe('math utility', () => {
  it('adds two numbers correctly', () => {
    expect(add(1, 2)).toBe(3);
  });
});

Run tests with npm run test.

Core Patterns

Unit Testing

Focus on pure functions and logic in src/main or packages/common. Use vi.mock() for dependencies.

• references/unit-testing-examples.md

Component Testing

Test React components in src/renderer. Focus on user interactions and props.

• references/component-testing-patterns.md

Mocking

Use centralized mock factories for consistent testing across components and contexts.

• references/mocking-guide.md - Mock factories and API patterns

Debugging Failing Tests

1. Read the error output and identify the failing assertion
2. Check mock setup — verify vi.mock() paths and return values match expectations
3. For component tests, inspect rendered output with screen.debug()
4. Run a single test in isolation: npm run test:node -- --no-color -t "test name"
5. Verify coverage: npm run test:coverage to confirm new code is tested

Advanced Usage

For detailed information:

• references/test-organization.md - Directory structure and naming
• references/running-tests.md - CLI commands and coverage
• references/best-practices.md - Principles and patterns
• references/test-patterns.md - Code templates
• assets/test-checklist.md - Pre-flight checklist