Update Enzyme to v3.x

[emilyrohrbough]

Issue Description

This is the most up-to-date version, plus v3.x provides support for > React 16! 🎉 They authors have even provided a v2 to v3 migration guide.

Issue Type

• New Feature
• Enhancement
• Bug
• Other

[bjankord]

@emilyrohrbough Haven't had a chance to look into this, do you know, is enzyme v3 compatible with react v15, or is it only compatible with react v16?

[emilyrohrbough]

V3 requires the configuration of a react adaptor, where the adaptor chosen is the react version listed as the project dependency. The configuration appears to be simple, including the following in a setup file:

import Enzyme from 'enzyme';
import Adapter from 'enzyme-adapter-react-16';

Enzyme.configure({ adapter: new Adapter() });

I'm not sure yet how this would tie in with our monorepo structure and current jest setup that creates global enzyme methods.

To be compatible with React 15 we will need to use the enzyme-adapter-react-15 adaptor, so to test both 15 & 16 we many need to look into setting up separate react testing environments.

[mhemesath]

I'd think it would be sufficient to just use enzyme-adapter-react-15.