I'm having endless trouble here at EDS with processes that divide testing into Systems Testing then Integrated Systems Testing then UAT. Of course I've heard the term before but never taken any notice.
It seems to me this harks back to old mainframe days where you could test your application in a test region then later connect it to some say downstream MIS warehouse or whatever.
In the modern context it's so difficult to draw a line between the centre and the edges - things are talking to each other all the time all the way through the functionality. However when I talk to the testing auditor, she can't see how you could jump straight into having all the components working.
Do you see any validity in this ST/IST concept? Are you constrained in this way?
This depends greatly on the format of the shop and the mission of the individual project or team. We run a multi-platform environment (not so much apples and oranges as it is mixed fruit salad).
For some projects, for some teams, we have little or no distinction between Systems Testing and Integrated Systems Testing. For others, there is a distinct difference.
When all the systems that need to be interfaced reside on the same platform type(s), it can be difficult to distinguish. Othertimes, we will stub in interfaces with external systems so we can focus on the primary system. When things look stable, remove the stubs and voila! IST just started.
in the "new world" of systems, there is a problem with mapping the individual types of testing that some auditing constraints put on each stage of the process.
Personally, with the systems I have worked on in the past, the stages you are mentioning have been combined. It is a stage where the system it being tested as a whole, but all the individual components are added into the same pool for interaction between one another.
Insanity: doing the same thing over and over again and expecting different results
When I did Systems Integration Testing that followed Systems testing it was to make sure that all of the interfaces to other systems worked.
We had a lot of applications that were integrated by interfaces. This can still occur in Financial systems where data from Accounts payable is interfaced into the General Ledger. This was always when the interfaces where some kind of batch that was weekly or monthly interface. And yes these were legacy mainframe applications.
Today the integration between applications is very often on line and immediate so all of the testing is often done during the System testing.
It may be that what System testing is where you are is actually component testing and then System Integration testing is full application or "end to end" testing.
I have not failed. I've just found 10,000 ways that won't work" --Thomas Edison