Data is not defined on this.$data

[tsiotska]

Using 'vue-test-utils' cannot call setData on wrapper because data exists only on "this" and not on "this.$data"
TypeError: Cannot add property dataText, object is not extensible
await wrapper.setData({dataText: 'Test'})

I added test case for that
https://github.com/tsiotska/vue-class-component/blob/fix/data-init/test/specs/test.spec.ts#L67
Could you give me some pointers how to fix this?

Also related:
vuejs/test-utils#572
vuejs/test-utils#1058