Laravel × React Jestでのテスト実行時のエラー

yarn test

Test suite failed to run

    Jest encountered an unexpected token

    This usually means that you are trying to import a file which Jest cannot parse, e.g. it's not plain JavaScript.

    By default, if Jest sees a Babel config, it will use that to transform your files, ignoring "node_modules".

    Here's what you can do:
     • To have some of your "node_modules" files transformed, you can specify a custom "transformIgnorePatterns" in your config.
     • If you need a custom transformation specify a "transform" option in your config.
     • If you simply want to mock your non-JS modules (e.g. binary assets) you can stub them out with the "moduleNameMapper" config option.

    You'll find more details and examples of these config options in the docs:
    https://jestjs.io/docs/en/configuration.html

    // babel.config.js
    module.exports = {
      presets: [
        '@babel/preset-env',
        '@babel/preset-react',
        '@babel/preset-flow',
      ],
      plugins: [
        'babel-plugin-styled-components',
        '@babel/plugin-proposal-class-properties',
      ]
    }

npm install babel-core@7.0.0-bridge.0 --save-dev

yarn test

yarn run v1.16.0
$ jest
 PASS  resources/js/tests/components/Sample.test.js
  <Sample />
    ✓ Snapshot (1ms)

Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        1.102s
Ran all test suites.
Done in 2.04s.

yarn test

yarn run v1.16.0
$ jest
/bin/sh: 1: jest: not found
error Command failed with exit code 127.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

yarn add jest