test(e2e): fix confusing decorator error logs (#2031)

e2e/cases/decorator/2022-03/index.test.ts

@@ -1,5 +1,5 @@
 import { test, expect } from '@playwright/test';
-import { build, gotoPage, rspackOnlyTest } from '@e2e/helper';
+import { build, gotoPage, proxyConsole, rspackOnlyTest } from '@e2e/helper';
 import { pluginBabel } from '@rsbuild/plugin-babel';
 
 test('should run stage 3 decorators correctly', async ({ page }) => {
@@ -37,6 +37,8 @@ rspackOnlyTest(
 test.fail(
   'stage 3 decorators do not support decoratorBeforeExport',
   async ({ page }) => {
+    const { logs, restore } = proxyConsole();
+
     // SyntaxError: Decorators must be placed *after* the 'export' keyword
     const rsbuild = await build({
       cwd: __dirname,
@@ -56,5 +58,15 @@ test.fail(
     expect(await page.evaluate('window.method')).toBe('targetMethod');
     expect(await page.evaluate('window.field')).toBe('message');
     await rsbuild.close();
+
+    expect(
+      logs.find((log) =>
+        log.includes(
+          'Using the export keyword between a decorator and a class is not allowed',
+        ),
+      ),
+    ).toBeTruthy();
+
+    restore();
   },
 );