test(ui): add tests for mobile menu default state and open/close behavior

Covers issue requirements:
- Menu is closed by default (dialog not in DOM)
- Opens when prop is set to true
- Closes when prop changes back to false
- Emits update:open on backdrop click
- Emits update:open on close button click

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: howwohmm

test/nuxt/components/Header/MobileMenu.spec.ts

@@ -0,0 +1,112 @@
+import { describe, it, expect, vi } from 'vitest'
+import { mockNuxtImport, mountSuspended } from '@nuxt/test-utils/runtime'
+import { ref, computed, nextTick } from 'vue'
+
+// Mock useConnector
+mockNuxtImport('useConnector', () => () => ({
+  isConnected: computed(() => false),
+  npmUser: computed(() => null),
+  avatar: computed(() => null),
+}))
+
+// Mock useAtproto
+mockNuxtImport('useAtproto', () => () => ({
+  user: computed(() => null),
+}))
+
+// Mock useFocusTrap (from @vueuse/integrations)
+vi.mock('@vueuse/integrations/useFocusTrap', () => ({
+  useFocusTrap: () => ({
+    activate: vi.fn(),
+    deactivate: vi.fn(),
+  }),
+}))
+
+describe('MobileMenu', () => {
+  async function mountMenu(open = false) {
+    const { MobileMenuClient } = await import('#components')
+    return mountSuspended(MobileMenuClient, {
+      props: {
+        open,
+        links: [
+          {
+            type: 'group' as const,
+            name: 'main',
+            label: 'Navigation',
+            items: [
+              { name: 'home', label: 'Home', to: '/', iconClass: 'i-lucide:home' },
+            ],
+          },
+        ],
+      },
+      attachTo: document.body,
+    })
+  }
+
+  it('is closed by default', async () => {
+    const wrapper = await mountMenu(false)
+    try {
+      // Menu content is behind v-if="isOpen" inside a Teleport
+      expect(document.querySelector('[role="dialog"]')).toBeNull()
+    } finally {
+      wrapper.unmount()
+    }
+  })
+
+  it('opens when the open prop is set to true', async () => {
+    const wrapper = await mountMenu(true)
+    try {
+      await nextTick()
+      const dialog = document.querySelector('[role="dialog"]')
+      expect(dialog).not.toBeNull()
+      expect(dialog?.getAttribute('aria-modal')).toBe('true')
+    } finally {
+      wrapper.unmount()
+    }
+  })
+
+  it('closes when open prop changes from true to false', async () => {
+    const wrapper = await mountMenu(true)
+    try {
+      await nextTick()
+      expect(document.querySelector('[role="dialog"]')).not.toBeNull()
+
+      await wrapper.setProps({ open: false })
+      await nextTick()
+      expect(document.querySelector('[role="dialog"]')).toBeNull()
+    } finally {
+      wrapper.unmount()
+    }
+  })
+
+  it('emits update:open false when backdrop is clicked', async () => {
+    const wrapper = await mountMenu(true)
+    try {
+      await nextTick()
+      const backdrop = document.querySelector('[role="dialog"] > button')
+      expect(backdrop).not.toBeNull()
+      backdrop?.dispatchEvent(new Event('click', { bubbles: true }))
+      await nextTick()
+      expect(wrapper.emitted('update:open')).toBeTruthy()
+      expect(wrapper.emitted('update:open')![0]).toEqual([false])
+    } finally {
+      wrapper.unmount()
+    }
+  })
+
+  it('emits update:open false when close button is clicked', async () => {
+    const wrapper = await mountMenu(true)
+    try {
+      await nextTick()
+      // Close button has aria-label matching $t('common.close') — find it inside nav
+      const closeBtn = document.querySelector('nav button[aria-label]')
+      expect(closeBtn).not.toBeNull()
+      closeBtn?.dispatchEvent(new Event('click', { bubbles: true }))
+      await nextTick()
+      expect(wrapper.emitted('update:open')).toBeTruthy()
+      expect(wrapper.emitted('update:open')![0]).toEqual([false])
+    } finally {
+      wrapper.unmount()
+    }
+  })
+})