refactor(tests): move font-google-multiple to standalone fixture and improve assertions

Moves the font-google-multiple fixture from a nested location inside
app-basic to a standalone fixture at tests/fixtures/font-google-multiple/.
This prevents side effects for other tests that build the app-basic fixture.

Updates the build test to remove misleading comments about reproducing #751.
The overwrittenRanges.push() fix in fonts.ts is a defensive consistency
improvement, not a fix for issue #751.

- Removes the nested fixture from app-basic/app/font-google-multiple/
- Creates minimal standalone fixture with package.json and vite.config.ts
- Updates test comments to clarify this tests general build validation
- Removes incorrect claim about reproducing #751

Author: Divkix

tests/fixtures/app-basic/app/font-google-multiple/globals.css

@@ -1,6 +1,5 @@
 import type { Metadata } from "next";
 import { Geist, Geist_Mono } from "next/font/google";
-import "./globals.css";
 
 const geistSans = Geist({
   variable: "--font-geist-sans",
@@ -13,8 +12,7 @@ const geistMono = Geist_Mono({
 });
 
 export const metadata: Metadata = {
-  title: "Create Next App",
-  description: "Generated by create next app",
+  title: "Font Google Multiple Test",
 };
 
 export default function RootLayout({

…asic/app/font-google-multiple/layout.tsx …ures/font-google-multiple/app/layout.tsxtests/fixtures/app-basic/app/font-google-multiple/layout.tsx renamed to tests/fixtures/font-google-multiple/app/layout.tsx tests/fixtures/app-basic/app/font-google-multiple/layout.tsx renamed to tests/fixtures/font-google-multiple/app/layout.tsx

@@ -1,8 +1,8 @@
-export default function FontGoogleMultiplePage() {
+export default function HomePage() {
   return (
     <main>
       <h1>Font Google Multiple Test</h1>
-      <p>This page tests multiple Google Fonts (Geist + Geist_Mono) in a layout.</p>
+      <p>This page tests multiple Google Fonts (Geist + Geist_Mono).</p>
     </main>
   );
 }

…-basic/app/font-google-multiple/page.tsx …xtures/font-google-multiple/app/page.tsxtests/fixtures/app-basic/app/font-google-multiple/page.tsx renamed to tests/fixtures/font-google-multiple/app/page.tsx tests/fixtures/app-basic/app/font-google-multiple/page.tsx renamed to tests/fixtures/font-google-multiple/app/page.tsx

@@ -0,0 +1,6 @@
+import { defineConfig } from "vite";
+import vinext from "vinext";
+
+export default defineConfig({
+  plugins: [vinext({ appDir: import.meta.dirname })],
+});

tests/fixtures/font-google-multiple/vite.config.ts

@@ -5,12 +5,12 @@ import os from "node:os";
 import { createBuilder } from "vite";
 import vinext from "../packages/vinext/src/index.js";
 
-const APP_FIXTURE_DIR = path.resolve(import.meta.dirname, "./fixtures/app-basic");
+const APP_FIXTURE_DIR = path.resolve(import.meta.dirname, "./fixtures/font-google-multiple");
 
 /**
  * Build an App Router fixture's RSC/SSR/client bundles using the actual Vite
  * build pipeline (createBuilder + buildApp). This exercises the full build
- * pipeline where issue #751 occurs, not just the transform hook in isolation.
+ * pipeline for font-google transforms.
  */
 async function buildFontGoogleMultipleFixture(): Promise<string> {
   const outDir = await fs.mkdtemp(path.join(os.tmpdir(), "vinext-font-google-multiple-"));
@@ -35,28 +35,38 @@ async function buildFontGoogleMultipleFixture(): Promise<string> {
     });
   };
 
+  const nodeModulesLink = path.join(APP_FIXTURE_DIR, "node_modules");
+
   try {
+    // Symlink node_modules before building so imports work
+    const projectNodeModules = path.resolve(import.meta.dirname, "../node_modules");
+    await fs.symlink(projectNodeModules, nodeModulesLink);
+
     const builder = await createBuilder({
       root: APP_FIXTURE_DIR,
       configFile: false,
-      plugins: [vinext({ appDir: APP_FIXTURE_DIR, rscOutDir, ssrOutDir, clientOutDir })],
+      plugins: [
+        vinext({
+          appDir: APP_FIXTURE_DIR,
+          rscOutDir,
+          ssrOutDir,
+          clientOutDir,
+        }),
+      ],
       logLevel: "silent",
     });
 
-    // This is where issue #751 occurs - during [1/5] analyze client references
     await builder.buildApp();
 
-    // Symlink node_modules for external imports
-    const projectNodeModules = path.resolve(import.meta.dirname, "../node_modules");
-    await fs.symlink(projectNodeModules, path.join(outDir, "node_modules"));
-
-    return path.join(outDir, "server", "index.js");
+    return path.join(outDir, "server", "index.mjs");
   } finally {
     globalThis.fetch = originalFetch;
+    // Cleanup symlink
+    await fs.unlink(nodeModulesLink).catch(() => {});
   }
 }
 
-describe("font-google build integration (issue #751)", () => {
+describe("font-google build integration", () => {
   let buildOutputPath: string;
   let outDir: string;
 
@@ -68,13 +78,9 @@ describe("font-google build integration (issue #751)", () => {
   });
 
   it("should build successfully with multiple Google fonts (Geist + Geist_Mono)", async () => {
-    // This test reproduces issue #751:
-    // Build fails during [1/5] analyze client references... with:
-    // Error: Unexpected token in app/layout.tsx at 234..235
-    //
-    // The issue occurs when using multiple fonts with the same options pattern:
-    // const geistSans = Geist({ variable: "--font-geist-sans", subsets: ["latin"] });
-    // const geistMono = Geist_Mono({ variable: "--font-geist-mono", subsets: ["latin"] });
+    // This test validates that the build pipeline can handle multiple
+    // Google font imports without errors. It exercises the font transform
+    // plugin during the full createBuilder + buildApp() flow.
     buildOutputPath = await buildFontGoogleMultipleFixture();
     outDir = path.dirname(path.dirname(buildOutputPath));