featureString = `${featuresPrefix}height=0`;
  var prefixedMessage = new PrefixedMessageTest();
  prefixedMessage.onMessage((data, e) => {
    e.source.close();
    runWindowTests(data);
  });
  var win = window.open(prefixedMessage.url(windowURL), '', featureString);
});

function runWindowTests (baselineDimensions) {
  // When code point in first position is not an ASCII digit, "+" or "-",
  // that's an error and the value becomes 0
  [ 'innerheight=/404',
    'innerheight=_404',
    'innerheight=L404'
 