test: handle proxy error message (#19319)

Author: sapphi-red

playground/proxy-bypass/__tests__/proxy-bypass.spec.ts

@@ -1,5 +1,5 @@
 import { expect, test, vi } from 'vitest'
-import { browserLogs, isServe, page, serverLogs } from '~utils'
+import { browserLogs, page, serverLogs } from '~utils'
 
 test('proxy-bypass', async () => {
   await vi.waitFor(() => {
@@ -12,7 +12,7 @@ test('async-proxy-bypass', async () => {
   expect(content).toContain('Hello after 4 ms (async timeout)')
 })
 
-test.runIf(isServe)('async-proxy-bypass-with-error', async () => {
+test('async-proxy-bypass-with-error', async () => {
   await vi.waitFor(() => {
     expect(serverLogs.join('\n')).toContain('bypass error')
   })

playground/proxy-bypass/vite.config.js

@@ -30,4 +30,18 @@ export default defineConfig({
       },
     },
   },
+  plugins: [
+    {
+      name: 'handle-error-in-preview',
+      configurePreviewServer({ config, middlewares }) {
+        return () => {
+          middlewares.use((err, _req, res, _next) => {
+            config.logger.error(err.message, { error: err })
+            res.statusCode = 500
+            res.end()
+          })
+        }
+      },
+    },
+  ],
 })