feat: frontend unit tests

frontend/tests/utils/helpers/translate.test.ts

@@ -0,0 +1,53 @@
+import { translateString } from '../../../src/static/js/utils/helpers/translate';
+
+declare global {
+    interface Window {
+        TRANSLATION?: Record<string, string>;
+    }
+}
+
+describe('js/utils/helpers', () => {
+    describe('translate', () => {
+        const originalReplacements = window.TRANSLATION;
+
+        beforeEach(() => {
+            delete window.TRANSLATION;
+        });
+
+        afterEach(() => {
+            window.TRANSLATION = originalReplacements;
+        });
+
+        test('Returns the same word when window.TRANSLATION is undefined', () => {
+            delete window.TRANSLATION;
+            expect(translateString('Hello')).toBe('Hello');
+            expect(translateString('NonExistingKey')).toBe('NonExistingKey');
+            expect(translateString('')).toBe('');
+        });
+
+        test('Returns mapped value when key exists in window.TRANSLATION', () => {
+            window.TRANSLATION = { Hello: 'Γεια', World: 'Κόσμος' };
+            expect(translateString('Hello')).toBe('Γεια');
+            expect(translateString('World')).toBe('Κόσμος');
+        });
+
+        test('Falls back to original word when key is missing in Twindow.RANSLATION', () => {
+            window.TRANSLATION = { Hello: 'Γεια' };
+            expect(translateString('MissingKey')).toBe('MissingKey');
+            expect(translateString('AnotherMissing')).toBe('AnotherMissing');
+        });
+
+        test('Supports empty string keys distinctly from missing keys', () => {
+            window.TRANSLATION = { '': '(empty)' };
+            expect(translateString('')).toBe('(empty)');
+            expect(translateString(' ')).toBe(' ');
+        });
+
+        test('Returns value as-is even if it is an empty string or falsy in the dictionary', () => {
+            window.TRANSLATION = { Empty: '', Zero: '0', False: 'false' };
+            expect(translateString('Empty')).toBe('');
+            expect(translateString('Zero')).toBe('0');
+            expect(translateString('False')).toBe('false');
+        });
+    });
+});