How can I still use DDD, TDD in BizTalk?

Question

I just started getting into BizTalk at work and would love to keep using everything I've learned about DDD, TDD, etc. Is this even possible or am I always going to have to use the Visio like editors when creating things like pipelines and orchestrations?

Answer 1

You can certainly apply a lot of the concepts of TDD and DDD to BizTalk development.

You can design and develop around the concept of domain objects (although in BizTalk and integration development I often find interface objects or contract first design to be a more useful way of thinking - what messages get passed around at my interfaces). And you can also follow the 'Build the simplest possible thing that will work' and 'only build things that make tests pass' philosophies of TDD.

However, your question sounds like you are asking more about the code-centric sides of these design and development approaches.

Am I right that you would like to be able to follow the test driven development approach of first writing a unti test that exercises a requirement and fails, then writing a method that fulfils the requirement and causes the test to pass - all within a traditional programing language like C#?

For that, unfortunately, the answer is no. The majority of BizTalk artifacts (pipelines, maps, orchestrations...) can only really be built using the Visual Studio BizTalk plugins. There are ways of viewing the underlying c# code, but one would never want to try and directly develop this code.

There are two tools BizUnit and BizUnit Extensions that give some ability to control the execution of BizTalk applications and test them but this really only gets you to the point of performing more controled and more test driven integration tests.

The shapes that you drag onto the Orchestration design surface will largely just do their thing as one opaque unit of execution. And Orchestrations, pipelines, maps etc... all these things are largely intended to be executed (and tested) within an entire BizTalk solution.

Good design practices (taking pointers from approaches like TDD) will lead to breaking BizTalk solutions into smaller, more modular and testable chunks, and are there are ways of testing things like pipelines in isolation.

But the detailed specifics of TDD and DDD in code sadly don't translate.

For some related discussion that may be useful see this question:

http://stackoverflow.com/questions/256897/mocking-webservice-consumed-by-a-biztalk-request-response-port#271044

Answer 2

Hi,

You could use BizUnit to create and reuse generic test cases both in code and excel(for functional scenarios)

http://www.codeplex.com/bizunit

BizTalk Server 2009 is expected to have more IDE integrated testability.

Cheers Hemil.

Answer 3

If you often make use of pipelines and custom pipeline components in BizTalk, you might find my own PipelineTesting library useful. It allows you to use NUnit (or whatever other testing framework you prefer) to create automated tests for complete pipelines, specific pipeline components or even schemas (such as flat file schemas).

It's pretty useful if you use this kind of functionality, if I may say so myself (I make heavy use of it on my own projects).

You can find an introduction to the library here, and the full code on github. There's also some more detailed documentation on its wiki.

Answer 4

BizUnit is really a pain to use because all the tests are written in XML instead of a programming language.

In our projects, we have "ported" parts of BizUnit to a plain old C# test framework. This allows us to use BizUnit's library of steps directly in C# NUnit/MSTest code. This makes tests that are easier to write (using VS Intellisense), more flexible, and most important, easier to debug in case of a test failure. The main drawback of this approach is that we have forked from the main BizUnit source.

Another interesting option I would consider for future projects is BooUnit, which is a Boo wrapper on top of BizUnit. It has advantages similar to our BizUnit "port", but also has the advantage of still using BizUnit instead of forking from it.

Answer 5

I agree with the comments by CKarras. Many people have cited that as their reason for not liking the BizUnit framework. But take a look at BizUnit 3.0. It has an object model that allows you to write the entire test step in C#/VB instead of XML. BizUnitExtensions is being upgraded to the new object model as well.

The advantages of the XML based system is that it is easier to generate test steps and there is no need to recompile when you update the steps. In my own Extensions library, I found the XmlPokeStep (inspired by NAnt) to be very useful. My team could update test step xml on the fly. For example, lets say we had to call a webservice that created a customer record and then checked a database for that same record. Now if the webservice returned the ID (dynamically generated), we could update the test step for the next step on the fly (not in the same xml file of course) and then use that to check the database.

From a coding perspective, the intellisense should be addressed now in BizUnit 3.0. The lack of an XSD did make things difficult in the past. I'm hoping to get an XSD out that will aid in the intellisense. There were some snippets as well for an old version of BizUnit but those havent been updated, maybe if theres time I'll give that a go.

But coming back to the TDD issue, if you take some of the intent behind TDD - the specification or behavior driven element, then you can apply it to some extent to Biztalk development as well because BizTalk is based heavily on contract driven development. So you can specify your interfaces first and create stub orchestrations etc to handle them and then build out the core. You could write the BizUnit tests at that time. I wish there were some tools that could automate this process but right now there arent.

Using frameworks such as the ESB guidance can also help give you a base platform to work off so you can implement the major use cases through your system iteratively.

Just a few thoughts. Hope this helps. I think its worth blogging about more extensively. This is a good topic to discuss.Do ping me if you have any questions or we can always discuss more over here.

Rgds Benjy