Testing

Unit tests for pure logic. Vitest runner.

Location

src/lib/ts/tests/*.test.ts

Run

yarn test              # all tests
yarn test --run        # single run (no watch)
yarn test --run src/lib/ts/tests/hits_3d.test.ts  # single file

Our Current Tests

Pure functions and math — things that don't need DOM or canvas:

• Coordinates — Point, Size, Rect arithmetic, transformations
• Angle — normalization, conversion, comparison
• Colors — parsing, blending, HSL/RGB conversion
• Extensions — array/number utilities
• hits_3d — geometry: point-in-polygon, segment proximity, front-facing detection

Style

import { describe, it, expect } from 'vitest';

describe('function_name', () => {
  it('does specific thing', () => {
    expect(result).toBe(expected);
  });
});

• One describe per function or concept
• Test names describe behavior, not implementation
• Use toBeCloseTo for floating point
• Inline helper functions for test data (e.g., proj(x, y, z, w))

Adding Tests

1. Create <name>.test.ts in src/lib/ts/tests/
2. Import from source: import { Thing } from '../types/Thing'
3. For private methods, copy the function into test file (tests the algorithm, not the class)

Visual Testing (future)

Vitest runs in Node — no browser, no canvas. For visual regression testing, add Playwright:

yarn add -D @playwright/test
npx playwright install

Workflow: captures screenshots, diffs against baseline PNGs in repo. Update baselines with --update-snapshots.