setName.test.js

import setName from './setName';

import {types} from 'babel-plugin-transform-flow-to-gen/api';
import type {Person} from './types';

require('jasmine-check').install();

describe('setName', () => {
  it.check('sets a new name', [Person(), types.string()], (person, newName) => {
    const next = setName(person, newName);
    expect(next.name).toEqual(newName);
    expect(person).not.toBe(next);
  });
});