Idea find iframe play button trailer

gistfile1.js

const getIframeDocument = () => {
  return cy
    .get('iframe[title="YouTube video player"]]')
    // Cypress yields jQuery element, which has the real
    // DOM element under property "0".
    // From the real DOM iframe element we can get
    // the "document" element, it is stored in "contentDocument" property
    // Cypress "its" command can access deep properties using dot notation
    // https://on.cypress.io/its
    .its('0.contentDocument').should('exist')
}

const getIframeBody = () => {
  // get the document
  return getIframeDocument()
    // automatically retries until body is loaded
    .its('body').should('not.be.undefined')
    // wraps "body" DOM element to allow
    // chaining more Cypress commands, like ".find(...)"
    .then(cy.wrap)
}

When('I click the play button', () => {
  getIframeBody().find('.ytp-large-play-button').click();
});

Then('the trailer should play', () => {
  // How do we check that it plays?
  // Could we check that the second counter is moving or something similar?
});