test: give each dev fixture its own vite cache

Author: danielroe

packages/nuxt-cli/test/utils/index.ts

@@ -1,4 +1,4 @@
-import{cp,rm,symlink}from'node:fs/promises'
+import{cp,mkdir,readdir,rm,symlink}from'node:fs/promises'
 import{join,sep}from'node:path'
 import{fileURLToPath}from'node:url'
 import{isCI}from'std-env'
@@ -28,6 +28,10 @@ export async function fetchWithPolling(url: string, options: RequestInit = {}, m
  * The dev e2e specs each wipe `.nuxt` and take the dev lock inside their
  * fixture, so pointing more than one of them at `fixtures/dev` makes them race
  * whenever vitest runs the files in parallel.
+ *
+ * Installed packages are linked in one by one rather than by symlinking
+ * `node_modules` wholesale, so that the caches tooling writes underneath it
+ * (`node_modules/.cache/vite`) belong to a single spec.
  */
 exportasyncfunctioncreateDevFixture(name: string): Promise<string>{
 constsource=fileURLToPath(newURL('../fixtures/dev',import.meta.url))
@@ -38,7 +42,15 @@ export async function createDevFixture(name: string): Promise<string> {
 recursive: true,
 filter: entry=>!entry.includes('node_modules')&&!entry.includes(`${sep}.nuxt`),
 })
-awaitsymlink(join(source,'node_modules'),join(target,'node_modules'),'junction')
+constsourceModules=join(source,'node_modules')
+consttargetModules=join(target,'node_modules')
+awaitmkdir(targetModules,{recursive: true})
+for(constentryofawaitreaddir(sourceModules)){
+if(entry==='.cache'||entry==='.vite'){
+continue
+}
+awaitsymlink(join(sourceModules,entry),join(targetModules,entry),'junction')
+}
 
 returntarget
 }