public void Set_Null_Removes()
{
var htmlDom = new HtmlDom();
var data = new BookData(htmlDom, new CollectionSettings(), null);
data.Set("1", "one", "en");
data.Set("1", null, "en");
Assert.AreEqual(null, data.GetVariableOrNull("1", "en"));
AssertThatXmlIn.Dom(htmlDom.RawDom).HasSpecifiedNumberOfMatchesForXpath("//div[@lang='en']", 0);
var roundTripData = new BookData(htmlDom, new CollectionSettings(), null);
Assert.IsNull(roundTripData.GetVariableOrNull("1", "en"));
}