However... -
Abstract
The role of testing in the development of software-based systems has changed significantly in the past few years. The 2013 release of the ISO/IEC 29119 software testing standard reflects this change, though the move towards risk- ...
The challenges
The verification of an embedded system that contains software faces several challenges. For instance: ...
The software state space
It is fairly easy to demonstrate that a modern, pre-emptible, embedded operating system (for instance, the QNX Neutrino OS or embedded Linux) with about 800 assembler instructions in its core has more than 10300 possible ...
Proven-in-use
Recently, Peter Ladkin published a very readable paper, Assessing Critical SW as “Proven-in-Use”: Pitfalls and Possibilities, that discusses how apparently simple changes to a program’s environment can invalidate all previous proven- ...
Why do we test?
Given its number of potential states, any tests of the sophisticated program that computes 2 + 2 cannot do more than scratch the surface of its state space. So why do companies bother with testing at all? A company performing testing on ...
Introducing a change
Given the enormous state space of our 2 + 2 program, it isn’t surprising that any modification could completely change its behavior.
For example, let’s say a new customer needs to know the value of 2 + 3. Could ...
However...
Given the number of states of software systems, the obvious question arises: “How does anything ever work?” We hear of many software-based systems that fail, but, of course, many continue to function correctly ...
Conclusion
We can never claim to have tested our software-based systems completely. Nor can we rely on confidence-from-use data gathered on one version of a system to give us figures for a slightly modified version ...