add server test suite

workers/site/__tests__/api-router.test.ts

@@ -0,0 +1,16 @@
+import { describe, it, expect, vi } from 'vitest';
+import { createRouter } from '../api-router';
+
+// Mock the vike/server module
+vi.mock('vike/server', () => ({
+  renderPage: vi.fn()
+}));
+
+describe('api-router', () => {
+  // Test that the router is created successfully
+  it('creates a router', () => {
+    const router = createRouter();
+    expect(router).toBeDefined();
+    expect(typeof router.handle).toBe('function');
+  });
+});