Testing is a first-order constituent of SOA governance. Assuring that services and service infrastructure components meet functional and technical requirements across lifecycle stages and environments, including production, is an architectural precept in SOA.
Gone are the days when testing was an isolated hop in the old disjointed SDLC. You know the one I'm talking about - an architect would design a component, hand it to developers to develop and they would hand it to testers to test, and testers, in turn, who would hand it to system administrators to operate. The components were often large, complex, and dependent on other complex components and systems, and so it was hard to write enough test cases to adequately assure quality.