(Medium) - Decouple Side-Effects

TestWithHttpServerDataSource.js

QUnit.test('Create a list of one post', (assert) => {
  const getRequest = (url) => {
    return Promise.resolve(`
      <section>
        <h1 class="post-title">How to bake a cake</h1>
      </section>
    `);
  };
  const httpServerDataSource = HttpServerDataSource(getRequest);
  const listOfPostTitles = ListOfPostTitles();
  listOfPostTitles.setDataSource(httpServerDataSource);
  return listOfPostTitles.toHtml().then((list) => {
    assert.strictEqual(list, '<ul><li>How to bake a cake</li></ul>');
  });
});