A failure in a SOA system at Heathrow resulted in a $3.2 mil one week loss.   Public gaffes such as this bring testing to the forefront.  How do you test SOA orchestration, load, and performance?  An SOA system could have layers of transactions, making testing complicated.  And as engineers know, testing is usually substandard on the easiest of systems.   KPI suggests that the testing begin at the same time of development.  Do not, under any circumstance, leave it to the end.   Computerworld has a SOA Testing primer online.