Next.js v12 compatibility

🐛 Bug Report

As this PR shows, next-page-tester has issues with Next.js v12. At a first sight I found:

• some types issues
• an unexpected segmentation fault error while running tests

I can’t predict when I’ll be able to work on it. As usual contributions are very welcome 🙌

Reproduction

https://github.com/toomuchdesign/next-page-tester/pull/280

[movahedan]

I don’t know if it is the exact issue you mentioned here or not, I get this Segmentation fault (core dumped) when I’m trying to test my pages after upgrading to next@12.0.2

This is my test:

        it('page renders and matches snapshot', async () => {
		const { serverRenderToString, render } = await getPage({
			route: '/_error',
		});

		// check correctness of SSR result
		const { html } = serverRenderToString();
		expect(html).toMatchSnapshot();

		// check hydrated app
		const { nextRoot } = render();
		expect(nextRoot.outerHTML).toMatchSnapshot();
	});

This information could be useful:

"next": "^12.0.2",
"react": "^17.0.2",
"react-dom": "^17.0.2",
"jest": "^27.1.0",
"babel-jest": "^27.1.0",

[calbrecht]

Maybe it has to do with https://github.com/nodejs/node/issues/40602. Debugging into await loadConfig where it tries to load the next.config.js file by calling await import is leading to the segfault.

–edit Probably more adequate issue because https://github.com/nodejs/node/issues/35889 is mentioning jest as well.