[FSSDK-12172] add setup for umd testing

.gitignore

@@ -16,4 +16,4 @@ local.log
 
 **/*.gen.ts
 
-.env
+.env

lib/index.umd.spec.ts

@@ -0,0 +1,23 @@
+import { expect, describe, it } from 'vitest';
+
+import * as optimizely from './index.browser';
+
+type OptimizelySdk = typeof optimizely;
+
+declare global {
+  interface Window {
+    optimizelySdk: OptimizelySdk;
+  }
+}
+
+describe('UMD Bundle', () => {  
+  // these are just intial tests to check the UMD bundle is loaded correctly
+  // we will add more comprehensive umd tests later
+  it('should have optimizelySdk on the window object', () => {
+    expect(window.optimizelySdk).toBeDefined();
+  });
+
+  it('should export createInstance function', () => {
+    expect(typeof window.optimizelySdk.createInstance).toBe('function');
+  });
+});