.childNodes.length, 2,
                  "Root element should have 2 children")
    assert_equals(doc.documentElement.firstChild.tagName, "HEAD");
    assert_equals(doc.documentElement.lastChild.tagName, "BODY");
    assert_equals(doc.documentElement.lastChild.childNodes.length, 1,
                  "Body element should have 1 child")
    assert_equals(doc.documentElement.lastChild.firstChild.tagName, "PRE");
    tD.done();
  })
  tC.step(function() {
    assert_equals(doc.documentElement.lastChild.firstChi