Vitest Browser Mode

import { defineConfig } from 'vitest/config';
import { defineBrowserTestConfig } from 'game-harness/vitest';

export default defineConfig({
  test: {
    projects: [
      {
        extends: true,
        test: { name: 'unit', environment: 'node', include: ['tests/unit/**'] },
      },
      {
        extends: true,
        test: defineBrowserTestConfig({
          optimizeDeps: ['three/examples/jsm/utils/SkeletonUtils.js'],
        }),
      },
    ],
  },
});

defineBrowserTestConfig() builds the test fragment for a real-Chromium Vitest Browser Mode project: headed by default (both locally and in CI, same as definePlaywrightConfig()), silent at the Chromium launch boundary, and a fixed viewport with deviceScaleFactor: 1 so a headed macOS run never recaptures visual baselines at the host's Retina scale. Pass headless: 'ci-only' only for a hosted runner genuinely without a display; CI should normally keep the headed default and run under xvfb-run. Requires vitest and @vitest/browser-playwright installed as peers.

optimizeDeps surfaces module specifiers (deep imports Vite's scanner won't discover on its own) that must also be merged into your top-level vite.config.ts's optimizeDeps.include — read them off the returned fragment's __optimizeDepsInclude field, since Vitest's test block has no optimizeDeps field of its own.