A couple years ago a was in a computer book club located in Philadelphia and participated remotely. The experience was great by unfortunately the group lost funding from Microsoft and disbanded.

After gauging a little bit of interest around town I have decided to try and start one here in Edmonton with the possibility of people being able to participate remotely.

If you are interested in participating, please join the discussion at the Google group mailing list.

Via Marc-Andre Cournoyer on Twitter, a reason for ASP.NET developers to switch to Rails: http://www.railsjedi.com/posts/15-Acts-as-ASP-NET-a-Ruby-on-Rails-Plugin-

Sadly, I bet I could sell Ruby and Rails to local businesses easier by showing them this page.

P.S. I am the altnet purse fight blog author. No one ever suspects the quiet guy.

Sweetness!

Today I was creating a test data builder for a unit test. I am fairly new to test data builders, on the last project I was on I relied on the ObjectMother pattern which became fairly tedious over time. Both the ObjectMother pattern and the Test Data Builder are Test Helper patterns:

"We define a helper class to hold any Test Utility Methods we want to reuse in several tests." 

If your objects aren't immutable and all you really care about is getting sensible test data without having to repeat yourself, you can use the Rhino Mocks GenerateStub feature to provide sensible test data and deal with invariant test data:

Once again be warned that this does not work for immutable objects, I don't recommend making value objects mutable just to implement this pattern so i'm not sure if it actually provides any real value. Maybe if it is combined with a mutable entity and a custom builder for a value object that preserves that value object's immutability. 

If anyone that reads this blog has a way to make Test Data Builders easier I would be glad to hear it.

[Currently Listening To: Young Galaxy- Young Galaxy - Wailing Wall]

For everyone that was at my DevTeach presentation thank you for showing up and listening to me. I had my adrenaline flowing and ended up finishing a little to early, if only I could code like that day to day!

If you have svn installed, you can download my presentation from the command line with the following command:

svn checkout http://stevenrockartspresentations.googlecode.com/svn/trunk/ devteachgenericspresentation

I still have to do one more check-in to add my reduce implementation and to clean up the code. I am also going to upload a zipped version of the code to the downloads section located here: http://code.google.com/p/stevenrockartspresentations/downloads/list

Here is a list of resources from the presentation:

- Combining Generics, Specifications and Functional Programming Part 1

- Combining Generics, Specifications and Functional Programming Part 2

- Combining Generics, Specifications and Functional Programming Part 3

- Combining Generics, Specifications and Functional Programming Part 4

- Follow up to Generics Presentation Feedback

- Reduce in C#

I got a couple of emails with great feedback from my lastcoupleofposts. I think I could probably turn this presentation into 2 different presentations but it is curing my blogging writers block so i'll post the responses here for everyone's benefit.

Shane was very quick to point out that the method signature in Customer is kind of misleading:

We could actually pass any specification that implements the ISpecification interface into this function. We can refactor a little to make it a little more clear to someone consuming the Customer class:

Using this approach we supply consumers of our class with a default for an active customer and allow them to specify their own specification for what constitutes an active customer.

One thing that I should have mentioned in my post is that Filter and Map are included in the List class in .NET 2.0. Filter == FindAll and Map==ConvertAll, here is the code from Reflector:

At my DevTeach presentation I showed how you can do Map and Filter from Functional programming right now in C# 2.0. In mathematics Reduce is "the process of manipulating a series of equations or matrices into a desired 'simpler' format". In C# you can think of it as taking a list and reducing it down to one value. 

Here is my implementation of Reduce in C# 2.0:

and the implementation of the tests:

The first test calculates the sum of adding all the integers in the list together using the add function. The second test takes an integer and concatenates it to a string producing a string of all the integers in the list.

The Reduce function introduces the default keyword that you can leverage with generics. This will give you the default value for value types (0 for integers, 0.0 for decimals, null for string).