add test for explicit locale

Author: amannn

Diff for: examples/example-app-router-playground/messages/de.json

@@ -3,7 +3,7 @@
     "hello": "Hallo {name}!"
   },
   "AsyncComponent": {
-    "basic": "AsyncComponent",
+    "basic": "AsyncComponent (de)",
     "markup": "Markup with <important>bold content</important>",
     "rich": "This is a <important>rich</important> text."
   },

Diff for: examples/example-app-router-playground/src/components/AsyncComponent.tsx

@@ -17,6 +17,15 @@ export default async function AsyncComponent() {
   );
 }
 
+export async function AsyncComponentGerman() {
+  const t = await getTranslations({locale: 'de', namespace: 'AsyncComponent'});
+  return (
+    <p data-testid="AsyncComponentGerman" lang="de">
+      {t('basic')}
+    </p>
+  );
+}
+
 export async function TypeTest() {
   const t = await getTranslations('AsyncComponent');
 

Diff for: examples/example-app-router-playground/tests/main.spec.ts

@@ -659,6 +659,13 @@ it('can use async APIs in async components', async ({page}) => {
     .getByText('AsyncComponent');
 });
 
+it('can use an explicit locale in an async component', async ({page}) => {
+  await page.goto('/de');
+  await expect(page.getByTestId('AsyncComponentGerman')).toHaveText(
+    'AsyncComponent (de)'
+  );
+});
+
 it('supports custom prefixes', async ({page}) => {
   await page.goto('/spain');
   await expect(page).toHaveURL('/spain');