nas-tools/dashboard/frontend/vitest.config.js

import { defineConfig } from 'vitest/config';
import { svelte } from '@sveltejs/vite-plugin-svelte';

const sveltePlugin = svelte({
  hot: !process.env.VITEST ? {
    preserveLocalState: true
  } : false,
  compilerOptions: {
    dev: true
  }
});

// Vitest 3 bundles its own Vite which may not expose `server.config.server`,
// causing the Svelte HMR plugin's configureServer to crash. Wrap it safely.
if (process.env.VITEST) {
  const plugins = Array.isArray(sveltePlugin) ? sveltePlugin : [sveltePlugin];
  for (const p of plugins) {
    if (p.configureServer) {
      const orig = p.configureServer;
      p.configureServer = function(server) {
        try { return orig.call(this, server); } catch (e) {
          if (!(e instanceof TypeError)) throw e;
        }
      };
    }
  }
}

export default defineConfig({
  plugins: [
    svelte({
      hot: !process.env.VITEST ? {
        preserveLocalState: true
      } : false,
      compilerOptions: {
        dev: true
      }
    })
  ],
  test: {
    globals: true,
    environment: 'jsdom',
    setupFiles: ['./tests/setup.js'],
    resetMocks: true,
    coverage: {
      provider: 'v8',
      reporter: ['text', 'html', 'lcov'],
      exclude: ['node_modules/', 'tests/', 'dist/', '*.config.js']
    }
  },
  resolve: {
    conditions: ['browser'],
    alias: {
      '@': '/src'
    }
  }
});