test(rsc): add e2e test for nested RSC outDir

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: hi-ogawa

packages/plugin-rsc/e2e/nested-outdir.test.ts

@@ -0,0 +1,54 @@
+import fs from 'node:fs'
+import path from 'node:path'
+import { expect, test } from '@playwright/test'
+import { setupInlineFixture, useFixture } from './fixture'
+import { defineStarterTest } from './starter'
+
+test.describe(() => {
+  const root = 'examples/e2e/temp/nested-outDir'
+
+  test.beforeAll(async () => {
+    await setupInlineFixture({
+      src: 'examples/starter',
+      dest: root,
+      files: {
+        'vite.config.base.ts': { cp: 'vite.config.ts' },
+        'vite.config.ts': /* js */ `
+import baseConfig from './vite.config.base.ts'
+
+// Modify baseConfig to use nested outDir (rsc inside ssr)
+baseConfig.environments.rsc.build.outDir = './dist/server/rsc'
+baseConfig.environments.ssr.build.outDir = './dist/server'
+
+export default baseConfig
+`,
+      },
+    })
+  })
+
+  test.describe('build-nested-outDir', () => {
+    const f = useFixture({ root, mode: 'build' })
+    defineStarterTest(f)
+
+    test('verify nested outDir structure', () => {
+      // RSC output exists inside SSR outDir
+      expect(fs.existsSync(path.join(f.root, 'dist/server/rsc/index.js'))).toBe(
+        true,
+      )
+      expect(
+        fs.existsSync(
+          path.join(f.root, 'dist/server/rsc/__vite_rsc_assets_manifest.js'),
+        ),
+      ).toBe(true)
+      // SSR output exists
+      expect(fs.existsSync(path.join(f.root, 'dist/server/index.js'))).toBe(
+        true,
+      )
+      expect(
+        fs.existsSync(
+          path.join(f.root, 'dist/server/__vite_rsc_assets_manifest.js'),
+        ),
+      ).toBe(true)
+    })
+  })
+})