Create-react-app: Test with Jest cause an error

[FateZeros]

I'm using creat-react-app , and want to use jest for testing.
But, It throws an error about matchMedia
Below this picture is my default test js

[Timer]

Did you try to include the polyfill as the error suggests?

[FateZeros]

I add a test-setup.js in /src

the test-setup.js is
window.matchMedia = window.matchMedia || function() { return { matches : false, addListener : function() {}, removeListener: function() {} }; };
and add <rootDir>/src/test-setup.js in setupFiles of jest in package.json
so the error is gone.

[Timer]

Closing as self-answered.
You might want to use an actual polyfill tho (https://github.com/paulirish/matchMedia.js/).

[gaearon]

For people who haven't ejected, defining polyfills in a file called src/setupTests.js should work.