Function createFixtureIframe

testing/iframe.js:52–193

(
  fixture,
  initialIframeHeight,
  opt_beforeLoad
)

 * }>}
 */
export function createFixtureIframe(
  fixture,
  initialIframeHeight,
  opt_beforeLoad
) {
  dev().assertNumber(
    initialIframeHeight,
    'Attempted to create fixture iframe with non-numeric height'
  );
  return new Promise((resolve, reject) => {
    // Counts the supported custom events.
    const events = {
      [AmpEvents_Enum.ATTACHED]: 0,
      [AmpEvents_Enum.DOM_UPDATE]: 0,
      [AmpEvents_Enum.ERROR]: 0,
      [AmpEvents_Enum.LOAD_END]: 0,
      [AmpEvents_Enum.LOAD_START]: 0,
      [AmpEvents_Enum.STUBBED]: 0,
      [AmpEvents_Enum.UNLOAD]: 0,
      [BindEvents.INITIALIZE]: 0,
      [BindEvents.SET_STATE]: 0,
      [BindEvents.RESCAN_TEMPLATE]: 0,
      [FormEvents.SERVICE_INIT]: 0,
    };
    let html = __html__[fixture] // eslint-disable-line no-undef
      .replace(
        /__TEST_SERVER_PORT__/g,
        window.ampTestRuntimeConfig.testServerPort
      );
    if (!html) {
      throw new Error('Cannot find fixture: ' + fixture);
    }
    html = maybeSwitchToMinifiedJs(html);
    window.ENABLE_LOG = true;
    // This global function will be called by the iframe immediately when it
    // starts loading. This appears to be the only way to get the correct
    // window object early enough to not miss any events that may get fired
    // on that window.
    window.beforeLoad = function (win) {
      // Flag as being a test window.
      win.__AMP_TEST_IFRAME = true;
      win.__AMP_TEST = true;
      // Set the testLocation on iframe to parent's location since location of
      // the test iframe is about:srcdoc.
      // Unfortunately location object is not configurable, so we have to define
      // a new property.
      win.testLocation = new FakeLocation(window.location.href, win);
      win.ampTestRuntimeConfig = window.ampTestRuntimeConfig;
      if (opt_beforeLoad) {
        opt_beforeLoad(win);
      }
      const messages = new MessageReceiver(win);
      // Function that returns a promise for when the given event fired at
      // least count times.
      const awaitEvent = (eventName, count) => {
        if (!(eventName in events)) {
          throw new Error('Unknown custom event ' + eventName);
        }