Enzyme has shallow render API as not depending on DOM, which is based on shallow renderer.
Shallow renderer has some limitations, which means it doesn't support refs and componentDid〜 lifecycle methods.
(Enzyme supports componentDid〜 lifecycle methods with some hacks)

React provides react-test-renderer, which supports refs for composite components and all lifecycle methods.
(refs for DOM returns null)

I think it's a good option for testing components without DOM even though react-test-render may not work with old versions(< 0.14) of React.

Also react-test-renderer is based on FiberReconciler, which means the renderer might be able to support many features Fiber provides.
What do you think?

Thanks.