<html>
<import src="../resources/chai.sky" />
<import src="../resources/mocha.sky" />
<script>
describe('MutationObserver.observe', function() {
  it('should observe attributes', function() {
    var observer = new MutationObserver(function() {});
    var element = document.createElement('div');
    element.setAttribute('data-test', '1');

    observer.observe(element, {attributeOldValue: true});
    element.setAttribute('data-test', '2');
    var records = observer.takeRecords();
    assert.equal(records.length, 1);
    assert.equal(records[0].oldValue, 1);
    observer.disconnect();

    observer.observe(element, {attributeOldValue: false});
    element.setAttribute('data-test', '3');
    var records = observer.takeRecords();
    assert.equal(records.length, 1);
    assert.isNull(records[0].oldValue);
    observer.disconnect();

    observer.observe(element, {attributeFilter: ['data-test']});
    element.setAttribute('data-test', '4');
    var records = observer.takeRecords();
    assert.equal(records.length, 1);
    assert.isNull(records[0].oldValue);
    observer.disconnect();
  });
});
</script>
</html>