public void TestListBooksByWriter()
{
IEnumerable <Book> books = new List <Book> {
new Book {
ID = 1, Title = "Title 1", WriterID = 1, Year = 1921
},
new Book {
ID = 2, Title = "Title 2", WriterID = 1, Year = 1921
},
};
bookRepository.ListBooksByWriter(1).Returns(books);
IEnumerable <Book> result = writerService.ListBooksByWriter(1);
Assert.NotNull(result);
Assert.Equal(2, result.Count());
}