Update HeaderItem unit test

tests/unit/HeaderItem.spec.ts

@@ -0,0 +1,23 @@
+import { shallowMount } from '@vue/test-utils'; 
+import { createRouter, createWebHistory } from 'vue-router'
+import routes from '@/router/assets/routes'
+import HeaderItem from '@/components/HeaderItem.vue'; 
+
+const router = createRouter({
+  history: createWebHistory(),
+  routes: routes,
+}) 
+
+describe('HeaderItem.vue', () => {
+  it('renders slots when passed', () => {
+    const wrapper = shallowMount(
+      HeaderItem,
+      {
+        global: {
+          plugins: [router]
+        }
+      }
+    );
+    expect(wrapper.html()).toContain('Wavelovers');
+  });
+});