VueJs＆Jest：测试渲染方法返回$ scopedSlots

Question

是否有一种测试功能组件的方法，该功能组件可以从this.$copedSlots.default()方法中返回render？

我所追求的例子：

组件

<script>
export default {
  name: 'TestComponent',
  props: {
    fields: {
      type: Object,
      default: () => {
        return {};
      },
    },
  },
  data() {
    return {
      inputs: this.fields,
    };
  },
  render() {
    return this.$scopedSlots.default({
      fields: this.inputs,
    });
  },
  watch: {
    fields(newValue) {
      this.inputs = newValue;
    },
  },
};
</script>

测试

describe('TestComponent.vue', () => {
  it('Returns correct fields when props.fields is passed', () => {
    const fields = {
      name: 'Jon Joe',
      email: 'jon@doe.com',
    };
    const wrapper = shallowMount(TestComponent, {
      propsData: { fields },
    });
    //... how to check props returned with the render() function
  });
});

此刻我在运行此测试时遇到错误

TypeError：this。$ scopedSlots.default不是函数