A quick post here about some things I've read lately about test automation.  Specifically the test execution methods and the different levels in software that it can be implemented against.

With Agile methods there is a heavy emphasis in TDD (Test Driven Development) to use Unit Testing and the harnesses that support it.  This is good, and about time for development to do some testing and automation of their own. 

Next we get into using these harnesses to create Integration level tests and to incorporate them into the build process as part of Continous Integration (CI).  Again, a good idea whose time has long been due.

Now we get to the higher level tools, harnesses and methods for doing the API and "below the surface" tests (as some have called getting under the 'skin').  This adds another layer of testing we can do on the system and help to improve the efficiency and effectiveness of the testing via automation.  I'm all for that.

Finally we get to the GUI layer (where most of the test automation work is still done today) and all the fun we have with that.

So as you can see there are different layers of the software that we can peel away to see and test via automation.  Hopefully some of those layers don't have too strong a smell and make your eyes water up.  Just like when you peel an onion.  And as part of that you cannot judge the software by its outer layer alone, you will need to do some peeling further down to make sure things really work the way they are supposed to.  This is the complexity issue we deal with in software in general.  Nowadays there is a lot of complexity in our systems.

At times this complexity makes us look at our systems as being like a big green Ogre, it just gets ugly.  But if we spend the time and effort to go beyond the surface we find it isn't all that bad.

Really... really.

I'll follow up another time with more details and findings about the various layers. Right now it is a bit late and I need my beauty sleep.  ;-)