testFindElement_works() {
    const isBody = (element) => element.tagName == 'BODY';
    const isP = (element) => element.tagName == 'P';
    const firstP = document.querySelector('p');
    const htmlElement = document.documentElement;

    // root is an element
    assertNull(googDom.findElement(document.body, functions.FALSE));
    assertEquals(firstP, googDom.findElement(document.body, isP));

    // root is the document
    assertEquals(htmlElement, googDom.findElement(document, functions.TRUE));
    assertNull(googDom.findElement(document, functions.FALSE));
    assertEquals(document.body, googDom.findElement(document, isBody));
    assertEquals(firstP, googDom.findElement(document, isP));
  }
@suppress {strictMissingProperties} suppression added to enable type
           checking