test-preprocessor.js

/**
 * Transpiles TypeScript to JavaScript code.
 *
 * @link https://github.com/facebook/jest/blob/master/examples/typescript/preprocessor.js
 * @copyright 2004-present Facebook. All Rights Reserved.
 */
const tsc = require('typescript');
const tsConfig = require('./tsconfig.json');

module.exports = {
    process(src, path) {
        if (path.endsWith('.ts') || path.endsWith('.tsx') || path.endsWith('.js')) {
            return tsc.transpile(src, tsConfig.compilerOptions, path, []);
        }
        return src;
    },
};

test-setup.js

/**
 * Defines the React 16 Adapter for Enzyme. 
 *
 * @link http://airbnb.io/enzyme/docs/installation/#working-with-react-16
 * @copyright 2017 Airbnb, Inc.
 */
const enzyme = require("enzyme");
const Adapter = require("enzyme-adapter-react-16");

enzyme.configure({ adapter: new Adapter() });

test-shim.js

/**
 * Get rids of the missing requestAnimationFrame polyfill warning.
 * 
 * @link https://reactjs.org/docs/javascript-environment-requirements.html
 * @copyright 2004-present Facebook. All Rights Reserved.
 */
global.requestAnimationFrame = function(callback) {
    setTimeout(callback, 0);
};