infra-sk/modules/page_object/page_object_element_karma_test.ts

import { PageObjectElement, Serializable } from './page_object_element';
import {
  TestBed,
  describePageObjectElement,
} from './page_object_element_test_cases';

describe('PageObjectElement on the browser', () => {
  // This div will contain the top-level element in the HTML provided via the test bed.
  let container: HTMLDivElement;

  before(() => {
    // The container's innerHTML will be overwritten at the beginning of each test case.
    container = document.createElement('div');
    document.body.appendChild(container);
  });

  after(() => {
    container.remove();
  });

  const testBed: TestBed = {
    setUpPageObjectElement: (html: string): Promise<PageObjectElement> => {
      container.innerHTML = html;

      // Make sure there is only one top-level element.
      if (container.childElementCount !== 1) {
        throw new Error(
          'the given HTML contains more than one top-level element'
        );
      }

      // Retrieve the top-level element and wrap it inside a PageObjectElement.
      const element = container.firstElementChild as HTMLElement;
      return Promise.resolve(new PageObjectElement(element));
    },

    evaluate: <T extends Serializable | void = void>(
      fn: (el: HTMLElement) => T
    ) => Promise.resolve(fn(container.firstElementChild as HTMLElement)),
  };

  describePageObjectElement(testBed);
});