From bb90295d263bb02b969d83e5ba8c67f5ba50e1ed Mon Sep 17 00:00:00 2001
From: DEV-bot <dev-no-reply@weircon.dk>
Date: Mon, 2 Mar 2026 02:46:44 +0000
Subject: [PATCH] test(i18n): harden shared loader locale normalization
 coverage (#257)

---
 frontend/tests/lobby-loader.parity.test.ts | 28 +++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/frontend/tests/lobby-loader.parity.test.ts b/frontend/tests/lobby-loader.parity.test.ts
index c04d0a1..896c1a0 100644
--- a/frontend/tests/lobby-loader.parity.test.ts
+++ b/frontend/tests/lobby-loader.parity.test.ts
@@ -1,10 +1,36 @@
 import { describe, expect, it } from 'vitest';
 
-import { collectLocaleParityIssues, LOBBY_I18N_CATALOG, SUPPORTED_LOCALES } from '../shared/i18n/lobby-loader';
+import {
+  collectLocaleParityIssues,
+  LOBBY_I18N_CATALOG,
+  normalizeLocale,
+  SUPPORTED_LOCALES,
+  translateCatalogPath,
+} from '../shared/i18n/lobby-loader';
 
 describe('shared lobby i18n loader parity', () => {
   it('keeps da/en translation parity in shared keyspace', () => {
     const issues = collectLocaleParityIssues(LOBBY_I18N_CATALOG, SUPPORTED_LOCALES);
     expect(issues).toEqual([]);
   });
+
+  it('normalizes browser-style locale tags to supported keyspace locales', () => {
+    expect(normalizeLocale('da-DK')).toBe('da');
+    expect(normalizeLocale('en-US')).toBe('en');
+    expect(normalizeLocale('fr-FR')).toBe('en');
+  });
+
+  it('resolves shared frontend ui keys with fallback-safe behavior', () => {
+    expect(
+      translateCatalogPath(LOBBY_I18N_CATALOG.frontend.ui as Record<string, unknown>, 'host.start_round', 'da-DK'),
+    ).toBe('Start runde');
+
+    expect(
+      translateCatalogPath(LOBBY_I18N_CATALOG.frontend.ui as Record<string, unknown>, 'app.language_label', 'en-US'),
+    ).toBe('Language');
+
+    expect(
+      translateCatalogPath(LOBBY_I18N_CATALOG.frontend.ui as Record<string, unknown>, 'host.non_existing_key', 'da'),
+    ).toBe('host.non_existing_key');
+  });
 });