public void Save_UpdatesBookInfoMetadataTags()
{
_bookDom = new HtmlDom(
@"<html><body>
<div class='bloom-page' id='guid3'>
<div lang='en' data-derived='topic'>original</div>
</div>
</body></html>");
var book = CreateBook();
book.OurHtmlDom.SetBookSetting("topic", "en", "Animal stories");
book.Save();
Assert.That(book.BookInfo.TagsList, Is.EqualTo("Animal stories"));
book.OurHtmlDom.SetBookSetting("topic", "en", "Science");
book.Save();
Assert.That(book.BookInfo.TagsList, Is.EqualTo("Science"));
}