Next/link makes Jest+Enzyme tests fail. — TypeError: The "url" argument must be of type string. Received type undefined

Bug report

Every component that contains a Next Link component is throwing an error while testing it.

Everything was working fine with Next 9.1.6.

This might relate to https://github.com/zeit/next.js/issues/9951 (?).

Describe the bug

Jest+Enzyme unit test suites are failing after upgrading NextJS from 9.1.6 to 9.2.1.

To Reproduce

Steps to reproduce the behavior, please provide code snippets or a repository:

1. npm i
2. jest
3. See error: TypeError: The "url" argument must be of type string. Received type undefined

Console Screenshot

Expected behavior

Unit tests that were passing with Next 9.1.6 should still pass after upgrading Next version.

System information

• OS: macOS
• Node: 12.13
• Version of Next.js: 9.2.1

[timswalling]

I had the same issue. In my case it was caused by an incomplete mock of window.location that was missing the pathname property.

[lipp]

@timswalling thanks for the hint! 👍 After adding pathname to window.location fake in the jest.setup.js file , tests are working again.

// jest.setup.js
Object.defineProperty(window, 'location', {
	value: {
		pathname: '',
	},
	writable: true,
})