public async Task DeleteAuthorTest()
        {
            var options = getDatabase("DeleteAuthorDB");

            await using (var context = new LibraryContext(options))
            {
                var manager = new LibraryManager(context);
                await manager.AddAuthor(SingleAuthor());

                await context.SaveChangesAsync();

                var checkDelete = await manager.DeleteAuthor(1);

                Assert.Equal(1, checkDelete);
            }
        }