feat: Add Vitest for unit testing translations in firebaseui-core

Author: exaby73

packages/firebaseui-core/package.json

@@ -22,7 +22,9 @@
     "dev": "tsup --watch",
     "lint": "tsc --noEmit",
     "format": "prettier --write \"src/**/*.ts\"",
-    "clean": "rimraf dist"
+    "clean": "rimraf dist",
+    "test": "vitest run",
+    "test:watch": "vitest"
   },
   "keywords": [
     "firebase",
@@ -40,9 +42,11 @@
     "zod": "^3.24.1"
   },
   "devDependencies": {
-    "typescript": "^5.7.3",
-    "tsup": "^8.0.1",
     "prettier": "^3.1.1",
-    "rimraf": "^6.0.1"
+    "rimraf": "^6.0.1",
+    "tsup": "^8.0.1",
+    "typescript": "^5.7.3",
+    "vite": "^6.2.0",
+    "vitest": "^3.0.7"
   }
 }

packages/firebaseui-core/src/translations.test.ts

@@ -0,0 +1,94 @@
+import { describe, it, expect } from 'vitest';
+import { getTranslation, type TranslationsConfig } from './translations';
+
+describe('getTranslation', () => {
+  it('should return default English translation when no custom translations provided', () => {
+    const translation = getTranslation('errors', 'userNotFound');
+    expect(translation).toBe('No account found with this email address');
+  });
+
+  it('should use custom translation when provided', () => {
+    const customTranslations: TranslationsConfig = {
+      en: {
+        errors: {
+          userNotFound: 'Custom error message',
+        },
+      },
+    };
+
+    const translation = getTranslation('errors', 'userNotFound', customTranslations);
+    expect(translation).toBe('Custom error message');
+  });
+
+  it('should use custom translation in specified language', () => {
+    const customTranslations: TranslationsConfig = {
+      es: {
+        errors: {
+          userNotFound: 'Usuario no encontrado',
+        },
+      },
+    };
+
+    const translation = getTranslation('errors', 'userNotFound', customTranslations, 'es');
+    expect(translation).toBe('Usuario no encontrado');
+  });
+
+  it('should fallback to English when specified language is not available', () => {
+    const customTranslations: TranslationsConfig = {
+      en: {
+        errors: {
+          userNotFound: 'Custom English message',
+        },
+      },
+    };
+
+    const translation = getTranslation('errors', 'userNotFound', customTranslations, 'fr');
+    expect(translation).toBe('Custom English message');
+  });
+
+  it('should fallback to default English when no custom translations match', () => {
+    const customTranslations: TranslationsConfig = {
+      es: {
+        errors: {
+          wrongPassword: 'Contraseña incorrecta',
+        },
+      },
+    };
+
+    const translation = getTranslation('errors', 'userNotFound', customTranslations, 'es');
+    expect(translation).toBe('No account found with this email address');
+  });
+
+  it('should work with different translation categories', () => {
+    const translation = getTranslation('messages', 'passwordResetEmailSent');
+    expect(translation).toBe('Password reset email sent successfully');
+  });
+
+  it('should handle partial custom translations', () => {
+    const customTranslations: TranslationsConfig = {
+      en: {
+        errors: {
+          // Only override one error message
+          userNotFound: 'Custom not found message',
+        },
+      },
+    };
+
+    const userNotFound = getTranslation('errors', 'userNotFound', customTranslations);
+    const wrongPassword = getTranslation('errors', 'wrongPassword', customTranslations);
+
+    expect(userNotFound).toBe('Custom not found message');
+    expect(wrongPassword).toBe('Incorrect password');
+  });
+
+  it('should handle empty custom translations object', () => {
+    const customTranslations: TranslationsConfig = {};
+    const translation = getTranslation('errors', 'userNotFound', customTranslations);
+    expect(translation).toBe('No account found with this email address');
+  });
+
+  it('should handle undefined custom translations', () => {
+    const translation = getTranslation('errors', 'userNotFound', undefined);
+    expect(translation).toBe('No account found with this email address');
+  });
+});

packages/firebaseui-core/vitest.config.ts

@@ -0,0 +1,12 @@
+import { defineConfig } from 'vitest/config';
+
+export default defineConfig({
+  test: {
+    // Use the same environment as the package
+    environment: 'node',
+    // Include TypeScript files
+    include: ['src/**/*.{test,spec}.{js,ts}'],
+    // Exclude build output and node_modules
+    exclude: ['node_modules/**/*', 'dist/**/*'],
+  },
+});