Addon Vitest: Support init in Vitest >= 3.2

code/addons/docs/src/preset.ts

@@ -212,11 +212,6 @@ export const resolvedReact = async (existing: any) => ({
   mdx: existing?.mdx ?? dirname(require.resolve('@mdx-js/react')),
 });
 
-const optimizeViteDeps = [
-  '@mdx-js/react',
-  '@storybook/addon-docs > acorn-jsx',
-  '@storybook/addon-docs',
-  'markdown-to-jsx',
-];
+const optimizeViteDeps = ['@mdx-js/react', '@storybook/addon-docs', 'markdown-to-jsx'];
 
 export { webpackX as webpack, docsX as docs, optimizeViteDeps };

code/addons/vitest/package.json

@@ -100,8 +100,8 @@
     "@types/micromatch": "^4.0.0",
     "@types/node": "^22.0.0",
     "@types/semver": "^7",
-    "@vitest/browser": "^3.1.1",
-    "@vitest/runner": "^3.1.1",
+    "@vitest/browser": "^3.2.0",
+    "@vitest/runner": "^3.2.0",
     "boxen": "^8.0.1",
     "es-toolkit": "^1.36.0",
     "execa": "^8.0.1",
@@ -119,7 +119,7 @@
     "tree-kill": "^1.2.2",
     "ts-dedent": "^2.2.0",
     "typescript": "^5.8.3",
-    "vitest": "^3.1.1"
+    "vitest": "^3.2.0"
   },
   "peerDependencies": {
     "@vitest/browser": "^3.0.0",

code/addons/vitest/src/updateVitestFile.test.ts

@@ -158,6 +158,135 @@ describe('updateConfigFile', () => {
     expect(updated).toBe(false);
   });
 
+  it('adds projects property to test config', async () => {
+    const source = babel.babelParse(
+      await loadTemplate('vitest.config.3.2.template.ts', {
+        CONFIG_DIR: '.storybook',
+        BROWSER_CONFIG: "{ provider: 'playwright' }",
+        SETUP_FILE: '../.storybook/vitest.setup.ts',
+      })
+    );
+    const target = babel.babelParse(`
+      /// <reference types="vitest/config" />
+      import { defineConfig } from 'vite'
+      import react from '@vitejs/plugin-react'
+
+      // https://vite.dev/config/
+      export default defineConfig({
+        plugins: [react()],
+        test: {
+          globals: true,
+        },
+      })
+    `);
+
+    const updated = updateConfigFile(source, target);
+    expect(updated).toBe(true);
+
+    const { code } = babel.generate(target);
+    expect(code).toMatchInlineSnapshot(`
+      "/// <reference types="vitest/config" />
+      import { defineConfig } from 'vite';
+      import react from '@vitejs/plugin-react';
+
+      // https://vite.dev/config/
+      import path from 'node:path';
+      import { fileURLToPath } from 'node:url';
+      import { storybookTest } from '@storybook/addon-vitest/vitest-plugin';
+      const dirname = typeof __dirname !== 'undefined' ? __dirname : path.dirname(fileURLToPath(import.meta.url));
+
+      // More info at: https://storybook.js.org/docs/next/writing-tests/integrations/vitest-addon
+      export default defineConfig({
+        plugins: [react()],
+        test: {
+          globals: true,
+          projects: [{
+            extends: true,
+            plugins: [
+            // The plugin will run tests for the stories defined in your Storybook config
+            // See options at: https://storybook.js.org/docs/next/writing-tests/integrations/vitest-addon#storybooktest
+            storybookTest({
+              configDir: path.join(dirname, '.storybook')
+            })],
+            test: {
+              name: 'storybook',
+              browser: {
+                provider: 'playwright'
+              },
+              setupFiles: ['../.storybook/vitest.setup.ts']
+            }
+          }]
+        }
+      });"
+    `);
+  });
+
+  it('edits projects property of test config', async () => {
+    const source = babel.babelParse(
+      await loadTemplate('vitest.config.3.2.template.ts', {
+        CONFIG_DIR: '.storybook',
+        BROWSER_CONFIG: "{ provider: 'playwright' }",
+        SETUP_FILE: '../.storybook/vitest.setup.ts',
+      })
+    );
+    const target = babel.babelParse(`
+      /// <reference types="vitest/config" />
+      import { defineConfig } from 'vite'
+      import react from '@vitejs/plugin-react'
+
+      // https://vite.dev/config/
+      export default defineConfig({
+        plugins: [react()],
+        test: {
+          globals: true,
+          projects: ['packages/*', {some: 'config'}]
+        }
+      })
+    `);
+
+    const updated = updateConfigFile(source, target);
+    expect(updated).toBe(true);
+
+    const { code } = babel.generate(target);
+    expect(code).toMatchInlineSnapshot(`
+      "/// <reference types="vitest/config" />
+      import { defineConfig } from 'vite';
+      import react from '@vitejs/plugin-react';
+
+      // https://vite.dev/config/
+      import path from 'node:path';
+      import { fileURLToPath } from 'node:url';
+      import { storybookTest } from '@storybook/addon-vitest/vitest-plugin';
+      const dirname = typeof __dirname !== 'undefined' ? __dirname : path.dirname(fileURLToPath(import.meta.url));
+
+      // More info at: https://storybook.js.org/docs/next/writing-tests/integrations/vitest-addon
+      export default defineConfig({
+        plugins: [react()],
+        test: {
+          globals: true,
+          projects: ['packages/*', {
+            some: 'config'
+          }, {
+            extends: true,
+            plugins: [
+            // The plugin will run tests for the stories defined in your Storybook config
+            // See options at: https://storybook.js.org/docs/next/writing-tests/integrations/vitest-addon#storybooktest
+            storybookTest({
+              configDir: path.join(dirname, '.storybook')
+            })],
+            test: {
+              name: 'storybook',
+              browser: {
+                provider: 'playwright'
+              },
+              setupFiles: ['../.storybook/vitest.setup.ts']
+            }
+          }]
+        }
+      });"
+    `);
+  });
+
   it('adds workspace property to test config', async () => {
     const source = babel.babelParse(
       await loadTemplate('vitest.config.template.ts', {

code/addons/vitest/src/updateVitestFile.ts

@@ -50,6 +50,31 @@ const mergeProperties = (
   }
 };
 
+/**
+ * Merges a source Vitest configuration AST into a target configuration AST.
+ *
+ * This function intelligently combines configuration elements from a source file (typically a
+ * template) into an existing target configuration file, avoiding duplicates and preserving the
+ * structure of both files.
+ *
+ * The function performs the following operations:
+ *
+ * 1. **Import Merging**: Adds new import statements from source that don't exist in target (determined
+ *    by local specifier name). Imports are inserted after existing imports.
+ * 2. **Variable Declaration Merging**: Copies variable declarations from source to target if they
+ *    don't already exist (determined by variable name). Variables are inserted after imports.
+ * 3. **Configuration Object Merging**: Merges the configuration object properties from source into
+ *    target's default export. Supports both direct object exports and function-wrapped exports
+ *    (e.g., `defineConfig({})`). The merging is recursive:
+ *
+ *    - Nested objects are merged deeply
+ *    - Arrays are concatenated (shallow merge)
+ *    - Primitive values are overwritten
+ *
+ * @param source - The source Babel AST (template configuration to merge from)
+ * @param target - The target Babel AST (existing configuration to merge into)
+ * @returns {boolean} - True if the target was modified, false otherwise
+ */
 export const updateConfigFile = (source: BabelFile['ast'], target: BabelFile['ast']) => {
   let updated = false;
   for (const sourceNode of source.program.body) {

code/addons/vitest/src/vitest-plugin/index.ts

@@ -29,6 +29,7 @@ import sirv from 'sirv';
 import { dedent } from 'ts-dedent';
 
 // ! Relative import to prebundle it without needing to depend on the Vite builder
+import { INCLUDE_CANDIDATES } from '../../../../builders/builder-vite/src/constants';
 import { withoutVitePlugins } from '../../../../builders/builder-vite/src/utils/without-vite-plugins';
 import type { InternalOptions, UserOptions } from './types';
 
@@ -151,6 +152,7 @@ export const storybookTest = async (options?: UserOptions): Promise<Plugin[]> =>
     staticDirs,
     previewLevelTags,
     core,
+    extraOptimizeDeps,
   ] = await Promise.all([
     getStoryGlobsAndFiles(presets, directories),
     presets.apply('framework', undefined),
@@ -159,6 +161,7 @@ export const storybookTest = async (options?: UserOptions): Promise<Plugin[]> =>
     presets.apply('staticDirs', []),
     extractTagsFromPreview(finalOptions.configDir),
     presets.apply('core'),
+    presets.apply('optimizeViteDeps', []),
   ]);
 
   const pluginsToIgnore = [
@@ -326,6 +329,8 @@ export const storybookTest = async (options?: UserOptions): Promise<Plugin[]> =>
 
         optimizeDeps: {
           include: [
+            ...extraOptimizeDeps,
+            ...INCLUDE_CANDIDATES,
             '@storybook/addon-vitest/internal/setup-file',
             '@storybook/addon-vitest/internal/global-setup',
             '@storybook/addon-vitest/internal/test-utils',

code/addons/vitest/templates/vitest.config.3.2.template.ts

@@ -0,0 +1,30 @@
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+import { defineConfig } from 'vitest/config';
+
+import { storybookTest } from '@storybook/addon-vitest/vitest-plugin';
+
+const dirname =
+  typeof __dirname !== 'undefined' ? __dirname : path.dirname(fileURLToPath(import.meta.url));
+
+// More info at: https://storybook.js.org/docs/next/writing-tests/integrations/vitest-addon
+export default defineConfig({
+  test: {
+    projects: [
+      {
+        extends: true,
+        plugins: [
+          // The plugin will run tests for the stories defined in your Storybook config
+          // See options at: https://storybook.js.org/docs/next/writing-tests/integrations/vitest-addon#storybooktest
+          storybookTest({ configDir: path.join(dirname, 'CONFIG_DIR') }),
+        ],
+        test: {
+          name: 'storybook',
+          browser: BROWSER_CONFIG,
+          setupFiles: ['SETUP_FILE'],
+        },
+      },
+    ],
+  },
+});