.waitForExpectedEvents(function()
              {
                  assert_false(sourceBuffer.updating, 'updating attribute is false');
                  assert_equals(sourceBuffer.mode, 'segments');
                  sourceBuffer.mode = 'segments';  // No exception should occur.
                  assert_equals(sourceBuffer.timestampOffset, 0.0);
                  sourceBuffer.timestampOffset = 10.123456789;  // No exception should occur.
                  assert_equals(sourceBuffer.timestampOffset, 10.1234