public void IsGettingAllAuthorsFromDatabase() { db.Authors.AddRange(FillAuthors()); db.Books.AddRange(FillBooks()); db.SaveChanges(); Author author = new Author { Id = 1, FirstName = "FirstName1", LastName = "LastName1" }; List <Book> expected = new List <Book> { new Book { Id = 1, Title = "title1", Genre = "genre1", AuthorId = 1 }, new Book { Id = 2, Title = "title2", Genre = "genre2", AuthorId = 1 } }; List <Book> result = authorServices .GetAuthorBooks(author); Assert.AreEqual(expected.Count, result.Count); }