humpty/test/exitWithCode.test.js

Makes sure your changelogs mention your breaking changes

import exitWithCode from "../src/exitWithCode";

describe("exitWithCode()", () => {
  /* eslint-disable no-console */
  beforeEach(() => {
    global.process = { exit: jest.fn() };
  });

  [0, 1].forEach(exitCode => {
    test(`should exit with code "${exitCode}"`, () => {
      exitWithCode(exitCode);
      expect(process.exit.mock.calls[0][0]).toBe(exitCode);
    });
  });
});