feat: remove cover page

src/components/LessonSidebar.test.ts

@@ -7,7 +7,7 @@ describe('LessonSidebar', () => {
   it('emits a move when one lesson is dropped on another', async () => {
     const designs = [createEmptyTeachingDesign('1.md'), createEmptyTeachingDesign('2.md')]
     const wrapper = mount(LessonSidebar, {
-      props: { designs, selectedId: designs[0]?.id ?? 'cover' },
+      props: { designs, selectedId: designs[0]?.id ?? null },
     })
 
     await wrapper.get('[data-index="0"]').trigger('dragstart')
@@ -15,4 +15,14 @@ describe('LessonSidebar', () => {
 
     expect(wrapper.emitted('move')?.[0]).toEqual([0, 1])
   })
+
+  it('does not render a cover navigation item', () => {
+    const designs = [createEmptyTeachingDesign('1.md')]
+    const wrapper = mount(LessonSidebar, {
+      props: { designs, selectedId: null },
+    })
+
+    expect(wrapper.text()).not.toContain('封面')
+    expect(wrapper.find('.lesson-sidebar-cover').exists()).toBe(false)
+  })
 })