Error when trying pass props in slot in Jest

Hello! I have to test my Tabs component which setup function looks like this:

  setup(props, { slots }) {
    const tabTitles = ref(slots.default().map((tab) => tab.props.title))
    const selectedTitle = ref(tabTitles.value[0])

    provide("selectedTitle", selectedTitle)
    return {
      selectedTitle,
      tabTitles,
    }
  },

Now there are several failing test methods due to the problem in the last line here:

import { mount, VueWrapper } from "@vue/test-utils"
import Tabs from "@/components/Tabs.vue"

const slots = {
  slots: {
    default: '<Tab title="Test">Test</Tab>',
  },
}

const wrapper: VueWrapper<any> = mount(Tabs, slots) // TypeError: Cannot read property 'title' of null
//...

How to fix it? And why it fails at all?

Note that my Tabs.vue must be used as below:

<Tabs>
  <Tab title="First tab">Some content</Tab>
</Tabs>

Node version: v14.17.4

I assume you have to register your custom Tab component as well so that it can be interpreted correctly on mount ( Mounting Options | Vue Test Utils )

import Tabs from "@/components/Tabs.vue"
import Tab from "@/components/??.vue"

const options = {
  slots: {
    default: '<Tab title="Test">Test</Tab>',
  },
  stubs: {
    Tab
  }
}

const wrapper: VueWrapper<any> = mount(Tabs, options)