First class support for class component

[lmiller1990]

Class component has no real use now we have composition API and good TypeScript integration, but we should still have some tests to make sure it works as expected w/ Vue Test Utils.

[lmiller1990]

This line causes class component not to render:

https://github.com/vuejs/vue-test-utils-next/blob/ed07b50146823e2f08b76ada7a9a69d025b8fe22/src/mount.ts#L231

[lmiller1990]

PR for basic support fixing issue in #239: #240

[lmiller1990]

Ok things seems fine in TS files, but not for class components in vue. files. May be a problem in vue-jest. vuejs/vue-jest#297

[lmiller1990]

Ok, I found the problem. vue-jest needs to be updated. I made a minimal repository demonstrating how to load SFCs using vue-class-component syntax here if anyone is interested.

[lmiller1990]

This will be out by the end of the week.

vuejs/vue-jest#300 and #244

[lmiller1990]

^^^ They are out. New projects on Vue CLI using class component and Jest should work just fine.