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Frustration, the game, photo by unlovalblesteve

Dot, dot, dot, dot, dot — tests are passing, looks like it’s time for lunch — dot, dot, dot, dot, F. F? F? But the code works. I know it does. I think it does. Why is my test failing?

One of the most frustrating times as a TDD developer is that moment when a test is failing and you don’t know why, as opposed to the more normal case where the test fails as expected. Here’s a grab bag of tips, tricks, hints, and thoughts to get us all through that difficult time.

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photo credit: theD40kid

A few years ago, I worked on a team that was trying to move the business side away from the waterfall method into more of an agile approach so there wouldn’t be such a disconnect between design and development. Since there was no blueprint on how design could be done in an agile fashion, resistance was very high. One of the major sticking points, however, was in documenting requirements. The business side controlled the process which meant no one could see or review the requirements until they were released by the analyst. In a world view of us vs. them, collaboration was not very high on their list.

Collaboration, however, is high on the list for agile development. So, how to resolve this conundrum and begin to merge the two teams.

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photo credit: Artshooter

Pathfinder Development is a Software Development company. A large part of our workforce consists of software developers. Yet when we hire our interns and junior developers out of school, we hire Computer Scientists. That may seem like small semantic potatoes, but to me it is emblematic of the deep gulf that exists between the graduates that computer science departments produce and what software development companies like Pathfinder really need.

We are not a Trade School

There are a few things that really get in the way of Comp Sci departments producing good software developers. One of these is the “we are not a trade school” attitude. If you complain to professors that they aren’t producing decent software development, dollars to donuts that this is the response you’ll get. As I’ve mentioned before, my parents are both math professors, so I’m more than a little familiar with the culture of academia. In mathematics, having your work applied to something practical is the ultimate indignity. Real mathematicians scorn anything applied!

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Last week, Karega Scott made a nice post on how Pure MVC makes development of Windows applications using C# simple. I thought I ll piggyback on this post and share some of my thoughts regarding this popular framework. I think the framework, if understood completely and adopted intelligently, has to offer some really cool benefits like :

• Light-weight messaging mechanism (using Notification/Observer patterns) between different parts of the application without having to create custom events/hooks all over the place.
• Highly Decoupled Components allowing abstraction and seperation of logic.
• The application’s testability is enhanced greatly because of the reason stated above.
• A Centralized singleton Facade component that mediates between the different components in the application.
• The use of commands in the framework can help in building complex applications that need to perform several different UI-driven functions.

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photo credit: Rennett Stowe

For a developer who’s new to pair programming, it can be overwhelming and
difficult to adapt to pair programming practices. As developers, often the natural
tendency is to hole away and solve our problems on our own: we thrive on the
thrill of achieving the solution. The satisfaction of arriving at that solution
on your own can make you feel good, but it has other costs. If you’re new to
pair programming and feeling initially discouraged about the dynamics of
pairing: Don’t give up! Pairing is a skill that must be developed and honed just
like any other one.

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Spam Wall, by freezelight

What with upward of two people saying nice things about last week’s post, I’ve decided to keep going with part two of a look at some real testing code.

Most code-heavy tutorials show the code but not the tests — I’m doing the opposite here, and showing the tests, but not much of the code. Also, although I’m presenting these tests in chunks, you should realize that there was a lot of back-and-forth from Cucumber to tests to code and some backtracking, most of which I’ll spare you from having to wade through.

At the end of last week, I had run through the tests for spam-prevention code which worked by limiting the rate at which a user could send messages to other users of a particular social networking site. Cucumber was involved, and I think I went off on a tangent about writing lots of tests.

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Spent some time playing around with Flash Catalyst, which was released by Adobe as a public Beta yesterday. I downloaded it today and got started on some of the tutorials Adobe labs has put up.
My impressions:
It’s pretty neat stuff. I could see myself prototyping with it, although Keynote and Acrobat are my tools of choice at the moment.
From my limited time working with it, Catalyst’s main function is to make it very easy to take Photoshop or Illustrator compositions and turn them into fully (front end) functional interfaces, complete with animations, transitions, fades, buttons states etc. One of the tutorials had me import artwork of a scrollbar, in 4 layers. Creating an actual scrollbar and hooking it up to a canvas was as easy as selecting the individual layers and telling catalyst which part of the scroll bar it was (up button, down button, track and thumb). It;s also super easy to connect user actions to specific screens (or states, as Catalyst calls them).

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Google recently announced a new netbook operating system to great fanfare: Chrome OS. It’s named after Google’s browser for a very good reason – all applications run within the browser framework, rather than being downloaded, installed and run atop the user’s desktop operating system. Much of the subsequent analysis has revolved around the battle of the titans that is expected to occur now that Google has moved directly onto Microsoft’s turf.

Here’s my take: Google’s approach is gonna win.

Why? Developers, developers, developers, developers. And installers, installers, installers, installers. Developers because people don’t buy computers to run operating systems – they buy them to run applications. And developers write those apps. Installers because having a seamless installation experience doubles or triples a software developer’s customer base. And nothing is more seamless than clicking on a link.

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I’ve been doing a good deal of PDF generation in Rails, and had to go through the process of comparing all the available techniques and frameworks in order to find the right solution for my needs.

Its great that there are so many tools out there, but it can be a daunting task to figure out which is best, which will scale, which will continue to grow and improve, and to evaluate the true ‘cost’ of free vs. commercial.

With all this info finally digested and sorted out,  I was surprised when I got a client request to be able to add a banner to an existing pdf, and from what I can  recall, none of the libraries I know about seem able to do this.  Right now, I’m in the middle of googling the hell out of it, but haven’t found my silver-bullet answer yet.  (maybe I should ask jeeves?)

I’ve done various searches and have come across a few categories of PDF tools:

1. Wrappers to existing pdf generation tools like fpdf, and iText
2. PDF Template tools where you build a pdf skeleton file, and bind values to it programmatically
3. Pure Ruby PDF Generation tools
4. PDF Readers and inspection tools

I did find a discussion about how this could work on Google Groups between Greg Brown creator of Prawn and Ruport, and James Healey developer of PDF::Reader, but that discussion basically ended with, “Yeah, that would be cool!”.

At this point I’m looking into the Origami library which is actually designed for pdf ‘security’ and testing, and isn’t explicitly designed for editing pdfs in this way, but at the moment its the leading candidate in my list.

Have I missed something? Is there an obvious way to do this in ruby/rails that I’m completely overlooking? (I haven’t looked very deeply at tools that shell out to the bigger libraries, but I wouldn’t rule them out)

The initial requirement was to be able to add a banner/header to an existing PDF, but I can see the complexities of determining how to shift the existing content down without screwing up all the formatting, so I think even being able to insert a coverpage might be a suffcient implementation for now. (Maybe I should be searching for pdf ‘merging’ instead of editing)

I’ll update you with my final solution in an upcoming blog post, and I’ll be covering all of the info I’ve learned on PDF Generation tools for Ruby and Rails  at this year’s WindyCityRails Conference on September 12th. Drop by http://windycityrails.org to register. (early registration ends Aug 1st)

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PureMVC is open source framework that allows creation of application using Model, View and Controller pattern, and was original designed for Flex, Air and Flash application. It has since been port to various languages include the .NET C# language. So when I first heard about it, several months ago, I was working on a pretty large WinForm application design around the MVP – Model, View and Presenter pattern.

Our presenters were responsible for handling the user interaction coming from the views by subscribing to events published by the views, and coordinating these actions with changes needs from the models such that these changes are then reflected back in the views themselves.

Although this approached work, it requires a lot of wiring and unwiring of events from the various presenters to views, presenters to model, and presenters to presenters. So the code quickly begins to look like the following:

public class presenter1

{

public event EventHandler<EventArgs> SomethingHappened;

public presenter1()

{

_model = new Model();

_model.StateChanged += OnModelChange;

_model.DocumentSaved += OnModelSaved;

_view = new View();

_view.OnMouseDown += OnMouseDown;

_view.OnMouseUp += OnMouseUp;

_view.OnMouseMove += OnMouseMove;

_view.OnMouseEnter += OnMouseEnter;

}

…

…

As you can see, for every user interaction on the view or model change a particular presenter is interested in, you must subscribe to an event, and if other presenters are interested in particular actions from views they are not responsible for, well, I’m sure you can get the picture. So act II, introduction of PureMVC framework for WinForms.

So exploring the capabilities of PureMVC framework, uncovered a simplification of our code. At its core, it consists of four singleton objects Model, View, Controller and Façade. The Model, View and Controller contain literal string references to Proxies which are data model, Mediators which provide and manage the user interface, and Commands which interact with the Proxies and Mediators or other commands.

But the simplification revolves around the Façade which is responsible to provide messaging throughout the core framework using an Observer notification scheme. So now our code quickly begins to look like the following:

public class presenter1 : Mediator

{

public presenter1()

{

}

public override void ListNotificationOfInterest()

{

return new List<string> { Nofication.ViewMouseClick, Notification.ModelChange,};

}

public override void HandleNofication(INofication notification)

{

switch(nofication.Name)

{

case Notification.ViewMouseClick:

Dosomething();

break;

}

}

…

…

public class presenter2 : Mediator

{

public presenter2()

{

}

public override void ListNotificationOfInterest()

{

return new List<string> { Nofication.ViewMouseClick,};

}

public override void HandleNofication(INofication notification)

{

switch(nofication.Name)

{

case Notification.ViewMouseClick:

DoSomethingFun();

break;

}

}

…

…

public partial class view1 : Page

{

…

…

protected void view_mouseclicked(object sender, MouseEventArgs e)

{

Façade.NotifyObserver(new PureMVC.Pattern.Notification(Notification.Name));

}

…

…

Both presenter1 and presenter2 state they are interested in Notication.MouseClick event, and view1 uses the Façade to notify both presenters that the user has clicked the mouse button. No need to publish and subscribe to any events outside what’s naturally needed in the view.

The only thing I dislike is the name references, but as long as we are using constants you should be fine.

Related Services: .Net Application Development, Custom Software Development

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