This is because Enzyme does not yet work with React 16 as it's in alpha version.
Enzyme
Enzyme is a JavaScript Testing utility for React that makes it easier to assert, manipulate,
and traverse your React Components' output.
Enzyme's API is meant to be intuitive and flexible by mimicking jQuery's API for DOM manipulation
and traversal.
Enzyme is unopinionated regarding which test runner or assertion library you use, and should be
compatible with all major test runners and assertion libraries out there. The documentation and
examples for enzyme use mocha and chai, but you
should be able to extrapolate to your framework of choice.
If you are interested in using enzyme with custom assertions and convenience functions for
testing your React components, you can consider using:
To get started with enzyme, you can simply install it with npm:
npm i --save-dev enzyme
Enzyme is currently compatible with React 15.x, React 0.14.x and React 0.13.x. In order to
achieve this compatibility, some dependencies cannot be explicitly listed in our package.json.
If you are using React 0.14 or React <15.5, in addition to enzyme, you will have to ensure that
you also have the following npm modules installed if they were not already:
npm i --save-dev react-addons-test-utils react-dom
If you are using React >=15.5, in addition to enzyme, you will have to ensure that you also have
the following npm modules installed if they were not already: