test(auto-install): mirror alias package setup; map ~package to dist and add yarn fixture

fix(auto-install): normalize built-ins to include both 'fs' and 'node:fs'

chore(auto-install): set peer rollup to ^4 per review

Author: CharlieHelps

.config/vitest.config.mts

@@ -8,7 +8,13 @@ export default defineConfig({
       path.join(path.dirname(testPath), '.snapshots', path.basename(testPath) + snapExt)
   },
   resolve: {
-    // Allow importing the current package under test via `~package`
-    alias: [{ find: /^~package$/, replacement: path.resolve(process.cwd()) }]
+    // Allow importing the current package under test via `~package`.
+    // Point directly at the built entry so dynamic imports in tests work consistently.
+    alias: [
+      {
+        find: /^~package$/,
+        replacement: path.resolve(process.cwd(), 'dist/index.js')
+      }
+    ]
   }
 });

packages/auto-install/src/index.ts

@@ -58,7 +58,15 @@ export default function autoInstall(opts: RollupAutoInstallOptions = {}): Plugin
     pkg = {};
   }
 
-  const installed = new Set(Object.keys(pkg.dependencies || {}).concat(builtinModules));
+  // Normalize core module names to include both `fs` and `node:fs` forms so we never try to
+  // install built-ins regardless of how Rollup reports them or how they are imported.
+  const coreModules = new Set<string>([
+    ...builtinModules,
+    ...builtinModules.filter((m) => m.startsWith('node:')).map((m) => m.slice(5)),
+    ...builtinModules.filter((m) => !m.startsWith('node:')).map((m) => `node:${m}`)
+  ]);
+
+  const installed = new Set([...Object.keys(pkg.dependencies || {}), ...coreModules]);
   const cmd = commands[manager];
 
   return {

packages/auto-install/test/fixtures/yarn/.gitkeep

@@ -0,0 +1 @@
+