setupTestEnvironment.js

// setup test environment for jest and jsdom to 
// allow code like window.location.href = '/'

// # setupEnvironment.js
const JSDOMEnvironment = require('jest-environment-jsdom');

module.exports = class JSDOMEnvironmentGlobal extends JSDOMEnvironment {
   constructor(config) {
      super(config);

      this.global.jsdom = this.dom;
      this.originalEnv = Object.assign({}, process.env);
      process.env.VARIABLE = 'something';
   }

   teardown() {
      this.global.jsdom = null;
      process.env = this.originalEnv;

      return super.teardown();
   }
};

// #package.json
"jest": {
   ...    
   "testEnvironment": "<rootDir>/test/setupEnvironment.js"
},