TDD, or not TDD?

I'm pretty convinced that TDD (or better yet, BDD) is the way to go. As usual when I get to this stage, I no longer care a lot to discuss the issue. However, I just hit on an interesting article... one that I find particularly weird.

Ravi's point appears to be that TDD is rather useless... and / or that Peter Norvig is a much better programmer than Ron Jeffries. The thing is, as I said here I managed to solve the whole thing in about 8 hours total. Worse, I only did that once I started with a consistent test-first approach, my previous 3 or 4 attempts ended in failure.

So. While I have a huge ego (not so huge not to accept Peter Norvig as a better programmer than me though), I have strong doubts that I'm a better programmer than Ron Jeffries. I think that Vlad's article hits on part of a problem: discovering an algorithm using TDD is at least difficult, if not impossible - and TDD was not meant for that. I also think that Ron simply gave up - in fact, I also did that, several times - because the effort required to figure out the solution was not warranted by the importance of the problem. He started on what was probably the wrong idea and hasn't tried to get out of that box and re-think. If you will, he is guilty of having a (wrong) design up-front [grin].

(In my case, the issue was never the algorithm: I had in mind from my first attempt the final algorithm: try to discover "forced" values, where a cell can only have a single value, and repeat that until there's no such constrained cell left; after that, go with a "greedy" recursive algorithm where the first possible value of a cell is chosen, the whole algorithm is re-invoked, and if no solution is found go back and try the next possible value. I must admit that Peter's optimization "try the cell with fewest possible values first" never crossed my mind.)

So. In my opinion, TDD / BDD is quite useful... even for writing a Sudoku program :)

Comments

Post a Comment

Popular posts from this blog

Posting dynamic Master / Detail forms with Knockout

Image
I have the following dynamic form in my GitHub Inventory project : I created the form with KnockoutJS , using some ideas from this article . The detail view looks like this: <table id="acquisition_items" class="jtable"> <thead> <tr> <th>Product Name</th> <th>Quantity</th> <th>Price</th> <th>Value</th> <th><button data-bind="click: addItem">[+]</button></th> </tr> </thead> <tbody data-bind="foreach: items"> <tr> <td> <input data-bind="value: ProductName" type="text" value="" /> </td> <td> <input data-bind="value: Quantity" type="text" value="" /> </td> <td>
Read more

Comparing Excel files, take two

Image
I already wrote this project once, on GitHub , but I can't say that I like the result. I wrote that code without TDD, mostly to see if I can still work in the "normal" fashion. I can, but I had a bug that took me a while to even discover and then was difficult to write tests for. I also hate the temporal dependency in that design (if you don't call the SortBy method first, the ExcludeRecords method will return incorrect results). Anyway; here's attempt number two, writing that code using TDD. Structure I start by creating my usual structure for projects of this type - a library for the logic, a console application for the main program and a test project for tests. I also use the Enable NuGet Package Restore option (right-click on the solution node) to add the three NuGet files that will allow someone to automatically download all the packages I'm referencing without wasting space in the source code repository. (Right now I've only added the Moq pa
Read more

EF Code First: seeding with foreign keys

This is just a quick tip, more for future reference for myself than anything else. When using Entity Framework Code First, one of the things you might want to do while developing the application is to seed your database with some test data. This can be something as easy as: protected override void Seed(InventoryDB context) { context.Products.AddOrUpdate( p => p.Name, new Product { Name = "Hammer", SalePrice = 11.99m, }, new Product { Name = "Nail Pack x100", SalePrice = 0.05m, }, new Product { Name = "Saw", SalePrice = 19.99m, }, new Product { Name = "Toolkit", SalePrice = 39.99m, } ); //... } (I am using the AddOrUpdate method so the code detects whether those products already exist and doesn't add them again if they do.) The Product class is quite simple and – most importantly – doesn't depend on any other: public class Product { public int Id { g
Read more