public async Task Save_VisitsAllValidLinks_WhenRootDocumentContainsLinks()
{
_dataFetcher.Fetch(Arg.Is("/")).Returns(Task.FromResult((new byte[0], "")));
_linkParser.FindLinks(Arg.Any <byte[]>(), Arg.Is("")).Returns(new string[] { "blog" });
await _sut.Save();
await _dataFetcher.Received().Fetch(Arg.Is("blog"));
}