Complex systems need testing to ensure that they work as they are
intended. But bugs can be subtle, particularly in embedded systems,
where specialized hardware and real-time responsiveness make
programming more challenging.
Fortunately, there are many available techniques for software
testing that can help us generate a comprehensive set of tests to
ensure that our system works properly. In this last part in this
series, we examine the role of validation in the overall design
methodology as well as the nuts-and-bolts techniques for creating a
good set of tests for a given program.
The first question we must ask ourselves is how much testing is
enough. Clearly, we cannot test the program for every possible
combination of inputs. Because we cannot implement an infinite number
of tests, we naturally ask ourselves what a reasonable standard of
thoroughness is.
One of the major contributions of software testing is to provide us
with standards of thoroughness that make sense. Following these
standards does not guarantee that we will find all bugs. But by
breaking the testing problem into subproblems and analyzing each
subproblem, we can identify testing methods that provide reasonable
amounts of testing while keeping the testing time within reasonable
bounds.
The two major types of testing strategies follow:
- Black-box methods generate tests without looking
at the internal structure of the program.
- Clear-box (also known as white-box)
methods generate tests based on the program structure.
In this concluding part in this series, we cover both types of
tests, which complement each other by exercising programs in very
different ways.
