test(nuxt): add tests for import protection plugin

packages/nuxt/src/core/plugins/import-protection.ts

@@ -1,7 +1,7 @@
 import { createRequire } from 'node:module'
 import { createUnplugin } from 'unplugin'
 import { logger } from '@nuxt/kit'
-import { isAbsolute, join, relative, resolve } from 'pathe'
+import { isAbsolute, join, relative } from 'pathe'
 import type { Nuxt } from '@nuxt/schema'
 import escapeRE from 'escape-string-regexp'
 
@@ -21,7 +21,7 @@ export const vueAppPatterns = (nuxt: Nuxt) => [
     [new RegExp(`^${escapeRE(m as string)}$`), 'Importing directly from module entry points is not allowed.']),
   ...[/(^|node_modules\/)@nuxt\/kit/, /^nitropack/]
     .map(i => [i, 'This module cannot be imported in the Vue part of your app.']),
-  [new RegExp(escapeRE(resolve(nuxt.options.srcDir, (nuxt.options.dir as any).server || 'server')) + '\\/(api|routes|middleware|plugins)\\/'), 'Importing from server is not allowed in the Vue part of your app.']
+  [new RegExp(escapeRE(join(nuxt.options.srcDir, (nuxt.options.dir as any).server || 'server')) + '\\/(api|routes|middleware|plugins)\\/'), 'Importing from server is not allowed in the Vue part of your app.']
 ] as ImportProtectionOptions['patterns']
 
 export const ImportProtectionPlugin = createUnplugin(function (options: ImportProtectionOptions) {

packages/nuxt/test/import-protection.test.ts

@@ -0,0 +1,47 @@
+import { describe, expect, it } from 'vitest'
+import { ImportProtectionPlugin, vueAppPatterns } from '../src/core/plugins/import-protection'
+
+const testsToTriggerOn = [
+  ['~/nuxt.config', 'app.vue', true],
+  ['./nuxt.config', 'app.vue', true],
+  ['./nuxt.config.ts', 'app.vue', true],
+  ['nuxt.config.ts', 'app.vue', true],
+  ['./.nuxt/nuxt.config', 'app.vue', false],
+  ['.nuxt/nuxt.config', 'app.vue', false],
+  ['nuxt', 'components/Component.vue', true],
+  ['nuxt3', 'components/Component.vue', true],
+  ['/root/node_modules/@vue/composition-api', 'components/Component.vue', true],
+  ['@vue/composition-api', 'components/Component.vue', true],
+  ['@nuxt/kit', 'components/Component.vue', true],
+  ['/root/node_modules/@nuxt/kit', 'components/Component.vue', true],
+  ['some-nuxt-module', 'components/Component.vue', true],
+  ['/root/src/server/api/test.ts', 'components/Component.vue', true],
+  ['src/server/api/test.ts', 'components/Component.vue', true]
+] as const
+
+describe('import protection', () => {
+  it.each(testsToTriggerOn)('should protect %s', async (id, importer, isProtected) => {
+    const result = await transformWithImportProtection(id, importer)
+    if (!isProtected) {
+      expect(result).toBeNull()
+    } else {
+      expect(result).toBeDefined()
+      expect(result).contains('unenv/runtime/mock/proxy')
+    }
+  })
+})
+
+const transformWithImportProtection = (id: string, importer: string) => {
+  const plugin = ImportProtectionPlugin.rollup({
+    rootDir: '/root',
+    patterns: vueAppPatterns({
+      options: {
+        modules: ['some-nuxt-module'],
+        srcDir: 'src/',
+        dir: { server: 'server' }
+      }
+    } as any)
+  })
+
+  return (plugin as any).resolveId(id, importer)
+}