public void When_AddNewBook_Then_Data_Is_Added() { //arrange var category = context.Categories.First(); var newBook = BookMock.GetValidBook(category); var booksCountBeforeAdd = context.Books.Count(); //act _bookRepository.Insert(newBook); unitOfWork.SaveChanges(); //assert var booksCountAfterAdd = context.Books.Count(); Assert.AreEqual(booksCountBeforeAdd + 1, booksCountAfterAdd); }