chore: add test to check locale message keys consistency (#329)

frontend/messages/strings.test.ts

@@ -0,0 +1,33 @@
+import { describe, it, expect } from 'vitest';
+import en from './en.json';
+import ja from './ja.json';
+import ptBR from './pt-BR.json';
+
+function getAllKeys(obj: unknown, prefix = ''): string[] {
+  if (typeof obj !== 'object' || obj === null) return [];
+  return Object.entries(obj as Record<string, unknown>).flatMap(([key, value]) => {
+    const fullKey = prefix ? `${prefix}.${key}` : key;
+    if (value && typeof value === 'object' && !Array.isArray(value)) {
+      return getAllKeys(value, fullKey);
+    }
+    return [fullKey];
+  });
+}
+
+describe('Locale message keys consistency', () => {
+  const locales = [
+    { name: 'en', data: en },
+    { name: 'ja', data: ja },
+    { name: 'pt-BR', data: ptBR },
+  ];
+
+  const base = locales[0];
+  const baseKeys = getAllKeys(base.data);
+
+  for (const locale of locales.slice(1)) {
+    it(`should have the same keys as ${base.name} in ${locale.name}`, () => {
+      const localeKeys = getAllKeys(locale.data);
+      expect(localeKeys).toEqual(baseKeys);
+    });
+  }
+});