After we have built our system, verification and validation
is that phase of software development that aims to
check that the software system meets its specification and
fulfills its intended purpose. More precisely, we can look
at verification and validation independently. And validation is the
activity that answers the question did we build the
right system. Did we build the system that the
customer wants? That will make the customer happy. Whereas verification
answers a different question which is did we build the system
right. So given a description of the system that is the one
that we derived from the customer through the collection of requirements
and then design and so on, did we build a system that
actually implements the specification that we defined? And when we look
at verification there's many, many ways of doing verification and in fact
in the mini course number four we will cover verification extensively. The
only thing I want to mention here is the fact that verification
can be performed at different levels. In particular, it can be
performed at the unit level in which we test that the individual
units work as a expected. Can be performed in the integration level
in which what we test is the interaction between the different units.
So we want to make sure that the different modules talk
to each other in the right way. And finally, there is system
testing in which we test the system as a whole and we
want to make sure that all the system, all the different pieces
of the system work together in the right
way. And this is also the level at which
then we will apply validation and some other
testing techniques like stress testing or robustness testing and
so on. And as I said I'm not going to say anything more on this topic because
we will cover verification, and validation, and testing in
particular in great details in mini course number four.