I have always been intrigued by a question – Are there hidden systems?
I would say, sometimes – Yes
Why is this useful to a tester? It serves as one more layer of perception which could explain an existing feature, or a hidden functionality.
Lets talk of a real life example. One of my colleagues went to get his blood tested in a lab. He paid for the tests and got a receipt, which had an id number on it. He took this receipt and went to the lab assistant who would collect the blood samples. The lab assistant collected blood in a vial and marked a number on it, the same number was then written on the receipt also. This number was different from the receipt number, which made my friend ask “Why 2 numbers?” To which the lab assistant said, that is for “our reference”. This new id used by the assistant was all that was needed to track the blood sample, ever since it was collected, to storing it, till the point of creating the reports. In the event, my friend wanted to know the results of his blood test he had to make a phone call to the lab and provide the receipt number and answer a few questions before he could get his results.
Now the point in telling you the whole story is that, Have you ever wondered what could happen to an entity in a system, once it has been assigned a unique id? For all you know it may not be as unique as you think. Whenever you come across a system do not rule out another system (internal or invisible or ghost or whatever you may call it) which may be using a whole new id to keep track of whatever the hidden system is supposed to do before it spews the result out to the “visible” system. Even if you consider modelling this entire workflow of a person going to the lab for a test up to the point of collecting his reports, there are different systems that may have to interact and each system may have its own id and recognition methods for a particular instance. Many a time we tend to overlook this, thinking that there is only one system at work.
ezeetester 