test(collapse): add collapse test (#317)

src/collapse/tests/Collapse.spec.tsx

@@ -6,6 +6,7 @@ describe('n-collapse', () => {
   it('should work with import on demand', () => {
     mount(NCollapse)
   })
+
   it('can customize icon', () => {
     const wrapper = mount(() => {
       return (
@@ -19,4 +20,74 @@ describe('n-collapse', () => {
     })
     expect(wrapper.find('.my-icon').exists()).toEqual(true)
   })
+
+  it('should work with `arrow-placement` prop', async () => {
+    const wrapper = mount(NCollapse, {
+      slots: {
+        default: () => <NCollapseItem name="1"></NCollapseItem>
+      }
+    })
+    expect(wrapper.find('.n-collapse-item').classes()).toContain(
+      'n-collapse-item--left-arrow-placement'
+    )
+
+    await wrapper.setProps({ arrowPlacement: 'right' })
+    expect(wrapper.find('.n-collapse-item').classes()).toContain(
+      'n-collapse-item--right-arrow-placement'
+    )
+  })
+
+  it('should work with nested structure', async () => {
+    mount(NCollapse, {
+      slots: {
+        default: () =>
+          h(
+            NCollapseItem,
+            { name: '1', title: 'test1' },
+            {
+              default: () =>
+                h(NCollapse, null, {
+                  default: () => h(NCollapseItem, { name: '2', title: 'test2' })
+                })
+            }
+          )
+      }
+    })
+
+    // todo: test display-directive
+    // I wanted to test this function, but I was bothered by the <transition-stub>
+  })
+
+  it('should work with `display-directive` prop', async () => {
+    mount(NCollapse, {
+      props: {
+        displayDirective: 'show'
+      },
+      slots: {
+        default: () =>
+          h(
+            NCollapseItem,
+            { name: '1', title: 'test' },
+            { default: () => h('div', null, { default: () => 'test' }) }
+          )
+      }
+      // todo: test display-directive
+      // I wanted to test this function, but I was bothered by the <transition-stub>
+    })
+  })
+
+  it('should work with `on-item-header-click` prop', async () => {
+    const onClick = jest.fn()
+    const wrapper = mount(NCollapse, {
+      props: {
+        onItemHeaderClick: onClick
+      },
+      slots: {
+        default: () => <NCollapseItem name="1"></NCollapseItem>
+      }
+    })
+    const triggerNodeWrapper = wrapper.find('.n-collapse-item__header')
+    await triggerNodeWrapper.trigger('click')
+    expect(onClick).toHaveBeenCalled()
+  })
 })