Chase Brammer Thinking in Code

Alex Uhlmann on Agile Testing and Unit Testing in Flex

I got an email from Alex Uhlmann answering some questions about Flex Unit testing, and pointed me to a presentation he gave at max on the topic!  I guess that he had to twist some fingers to get the people at Adobe TV to post it

Here is the link

And embedded for your viewing pleasure.

Flex Unit Testing

Unit testing rocks.  It makes big projects less buggy, takes costs down, and in general is best practice for RIA development.  On top of all that, the hours spent searching through thousands of lines of code to eliminate a simple error all but goes away!  In the end testing is like source control.  You don't know how much you need until you start using it.

So what is unit testing?

"It's about figuring out what you are trying to do before you run off to try to do it. You write a specification that nails down a small aspect of behavior in a concise, unambiguous, and executable form. It's that simple. Does that mean you write tests? No. It means you write specifications of what your code will have to do. It means you specify the behavior of your code ahead of time. But not far ahead of time. In fact, just before you write the code is best because that's when you have as much information at hand as you will up to that point."

Who uses it?

“The fact of the matter is, not only is Adobe Consulting leveraging FlexUnit each and every day on our projects, but we continue to be advocates to our customers of using FlexUnit on their projects.”

Steven Webster
Adobe Consulting
cairngorm framework core contributor

What are the benefits of using TDD?

• Faster overall development
• Less expensive (development and maintenance cycles)
• Less complicated code bases
• More independent and reusable code
• Less time and problems with regression testing
• Break new ground

What are some of the cons of TDD?

• Developer learning curve
• Slower initial development speed
• Problems with a MVC type framework (Nimbus, Cairngorm, PureMVC)
• Poor Documentation

Implementation

Ok, so by now you should be convinced that Unit Testing will save you time, money, and sleepless nights.  But does FlexUnit play well with existing frameworks like Nimbus, Cairngorm, and PureMVC?  In short.  Not really.  FlexUnit can do it, but in a hackish way.  Adobe is trying to fix this though.  They are integrating FlexUnit into the next release of Flex, Flex 4!  Flex 4's release date is sometime in the 4th quater of 2009.

Until then, what do we do? Wait for more docs from Adobe!  Alex Uhlmann, a really nice guy who also happens to be a Flex Ninja at Adobe consulting responded to an email saying:

Yes I and many others within AC use TDD. I understand your frustration with the lack of information out there. I've talked at the last MAX conference about it and AFAIK this will be on Adobe TV soon. I'll ask when exactly. Also, I plan on publishing a lot more around this area.  [...]  I've sent some emails to Adobe folks to find out when my video will be released.

Current Course of Action

In lieu of Flex 4 and better integrated Unit Testing in the Flex Builder, what should we do?  Keep making your code testable wherever possible!  In projects that are leveraging frameworks like Nimbus or Cairngorm most of the business logic will be executed in the Command classes.  But that does not mean that the business logic of an application should reside in the commands themselves.  There are many views on where business logic should reside (commands, model, helpers), but for making testable and getting more code coverage, the best practice for now will most likely be putting as much code into self contained utility classes and objects.  This makes for better testing, and gets more code coverage!

Unknown classes, and classes to XML

In working on preparing some stuff for a training I am doing on Unit Testing in Flex, I wanted to find a way that I could reference any class, and any method in that class without ever knowning the actual class name or method names.  This is a pretty slick solution that will go through and add all of my test case methods to my FlexUnit testing suite.

1) I needed to call the class, but do it without ever knowing its name.  The way to do this is using getQualifiedClassName to get a string of the class.  Fully qualified means that it is the full path, so something like "com.chasebrammer.samples.TestClass"

2) I needed to call the class based off of its qualifiedName.  To do this, I used a little used native method called getDefinitionByName

3) After getting what class I am calling from, I wanted to get all of the method names in that class, and find any that have the name "test" on the front, and add them to my testSuite.  To get the xml of an object (or class), it is actually really simple, here is an example.  Then it was just a matter of looping the code to find the right methods and add them to the test suite.  So, below is the code, I find code talks better than description of code.

private function createSuite():TestSuite {
   var ts:TestSuite = new TestSuite();
   var className:String = getQualifiedClassName(this);
   addTests(ts, getDefinitionByName(className) as Class);
   return ts;
}
 
private function addTests(suite:TestSuite, testerClass:Class):void {
   var desc:XML = describeType(new testerClass("method"));
   for each(var method:XML in desc.method) {
      if (method.@name.substr(0, 4) == "test")
      suite.addTest(new testerClass(method.@name));
   }
}

Data Encryption in Adobe AIR

Daniel Dura - a really cool AIR Platform evangelist from Utah that I have met a few times at different flash user group meetings - just posted a great video on encrypting data in AIR.

I just wanted to point out how awesome AIR is that there is a single method in Flex to encrypt data - the EncryptedLocalStore feature, and it will switch between the different most secure encryption methods for different operating systems.  For Macs it will default to using the Keychain, and for Windows it will default to using the DPAPI.

What is cool too, is because EncryptedLocalStore uses just a simple ByteArray to store data, you can encrypt almost anything you can load into the Flash Player - images, swf's, text ... anything really.

Now, my question of curiousity, does anyone know what it uses for Linux?