Adding a Link to a React component was easy as it sounds, except that it broke half of the unit tests. I started getting “Invariant Violation: You should not use <Link> outside a <Router>” which explains itself, but sorting it out took quite some time. In my component I’ve been using withRouter, but the tests are done on a disconnected component without the router and the Link component requires the router context. While mostly understood the issue, when trying most of the suggestions, I kept getting the above error, or “Warning: Failed context type: The context
router is marked as required in
Component, but its value is
undefined“. So let’s see how to pass the router context to child components when testing in Enzyme/Jest.