public async void should_add_only_new_articles()
{
int scrappedArticlesCount = 5;
int articlesInDbCount = 2;
var scrappedArticles = new ArticleBuilder().Build(scrappedArticlesCount);
ArticlesResponseViewModel scrappedArticlesResponse = new()
{
Articles = scrappedArticles
};
List <ArticleDb> articlesInDb = scrappedArticles.Take(articlesInDbCount).ToList().Map();
List <Article> articlesToAdd = null;
Action <object> mapArticlesToAdd = (list) => { articlesToAdd = list as List <Article>; };
List <Article> expectedResult = scrappedArticles.TakeLast(3).ToList();
_pagesScrapperService.Setup(n => n.ScrapAll()).ReturnsAsync(scrappedArticlesResponse);
_articlesRepository.Setup(n => n.Get(null, null, "")).Returns(articlesInDb);
_mapper.Setup(n => n.Map <List <ArticleDb> >(It.IsAny <List <Article> >())).Callback(mapArticlesToAdd);
await _sut.Scrap();
articlesToAdd.Should().BeEquivalentTo(expectedResult);
}