correct render function to add role attribute

role 'group' add to list wrap
Add unit test to aria roles and states.

Author: mash19

index.js

@@ -455,7 +455,9 @@
                         'padding-bottom': delta.paddingBottom + 'px'
                     },
                     'class': this.wclass,
-                    'role': 'group'
+                    attrs: {
+                        'role': 'group'
+                    }
                 }, list)
             ])
         }

test/aria.test.js

@@ -0,0 +1,64 @@
+import VirtualList from '../index'
+import { mount } from '@vue/test-utils'
+import { getIndexList } from './util'
+
+// for testing base build.
+const theme = 'aria-test'
+
+describe(theme, () => {
+    const listCount = 1000
+    const wrapper = mount({
+        template: `
+            <div id="app" style="width: 300px;">
+                <virtual-list class="list"
+                    role="list"
+                    :size="40"
+                    :remain="6"
+                    wclass="group"
+                >
+                    <div class="for-item"
+                        v-for="(item, index) in items"
+                        :key="index"
+                        style="height: 40px; line-height: 40px;"
+                        role="list-item"
+                        :aria-setsize="listCount"
+                        :aria-posinset="index"
+                    >
+                        <span class="for-item-text">{{ item }}</span>
+                    </div>
+                </virtual-list>
+            </div>
+        `,
+
+        name: 'test',
+
+        components: {
+            'virtual-list': VirtualList
+        },
+
+        data () {
+            return {
+                items: getIndexList(listCount),
+                listCount
+            }
+        }
+    })
+
+    it('check to see if aria role "list" is set on parent', () => {
+        const role = wrapper.find('.list').attributes('role');
+        expect(role).toBe('list')
+    });
+    it('check to see if aria role "group" is set on list container', () => {
+        const groupRole = wrapper.find('.list > .group').attributes('role')
+        expect(groupRole).toBe('group')
+    });
+    it('check to see if aria roles and states are set on list items', () => {
+        const itemFrags = wrapper.findAll('.for-item')
+        const allListItemsTest = itemFrags.wrappers.every((x, i) => {
+           return x.attributes('role') === 'list-item'
+            && x.attributes('aria-setsize') === listCount.toString() 
+            && x.attributes('aria-posinset') === i.toString()
+        })
+        expect(allListItemsTest).toBe(true)
+    });
+})