Function createAmpElementForTesting

src/custom-element.js:2176–2189

(
  win,
  opt_implementationClass,
  opt_elementConnectedCallback
)

 * @visibleForTesting
 */
export function createAmpElementForTesting(
  win,
  opt_implementationClass,
  opt_elementConnectedCallback
) {
  const Element = createCustomElementClass(
    win,
    opt_elementConnectedCallback || (() => {})
  );
  if (getMode().test && opt_implementationClass) {
    Element.prototype.implementationClassForTesting = opt_implementationClass;
  }
  return Element;
}

/**
 * @visibleForTesting