Basic Jest config

wallaby.js

module.exports = function (wallaby) {
  return {
    files: [
      { pattern: 'node_modules/babel-polyfill/dist/polyfill.js', instrument: false },
      'config/jest.setup.js',
      'src/**/*.js',
      'package.json',
      '!**/*[sS]pec.js',
      '!**/*[tT]est.js',
      '!node_modules/**/*.*',
      ],

    tests: [
      '!node_modules/**/*.*',
      '**/*[sS]pec.js',
      '**/*[tT]est.js',
    ],

    env: {
      type: 'node',
      runner: 'node',
    },

    debug: true,

    testFramework: 'jest',

    compilers: {
      '**/*.js': wallaby.compilers.babel(),
    },
    setup: function (wallaby) {
      let jestConfig = require('./package.json').jest;
      // for example:
      // jestConfig.globals = { "__DEV__": true };
      wallaby.testFramework.configure(jestConfig);
    },
  };
};