Information Technology Reference
In-Depth Information
1.2.4 The Four Primary Objectives of Testing
Testing can be applied to a wide range of development projects in a large number
of industries. In contrast to the diversity of testing opportunities, there is a common
underpinning of objectives. The primary motivation for testing all business
development p r oj e c t s i s t h e s a m e : t o r e d u c e t h e risk of unplanned development expense
or, worse, the risk of project failure. This development risk can be quantifi ed as some
kind of tangible loss such as that of revenue or customers. Some development risks
are so large that the company is betting the entire business that the development will
be successful. In order to know the size of the risk and the probability of it occurring,
a risk assessment is performed. This risk assessment is a series of structured “what
if” questions that probe the most likely causes of development failure depending on
the type of development and the type of business the development must support. This
risk motivation is divided into four interrelated testing objectives.
Primary objectives of testing
Testing objective 1: Identify the magnitude and sources of development risk
reducible by testing.
When a company contemplates a new development project, it prepares a business
case that clearly identifi es the expected benefi ts, costs, and risks. If the cost of the
project is not recovered within a reasonable time by the benefi ts or is determined to be
a bad return on investment, the project is deemed unprofi table and is not authorized
to start. No testing is required, unless the business case is tested. If the benefi ts
outweigh the costs and the project is considered a good return on investment, the
benefi ts are then compared to the risks. It is quite likely that the risks are many times
greater than the benefi ts. An additional consideration is the likelihood that the risk
will become a real loss. If the risk is high but the likelihood of the risk occurring is
very small, then the company typically determines that the risk is worth the potential
benefi t of authorizing the project. Again, no testing is required.
If the risk is high and the likelihood of its occurrence is high, the questions “Can this
risk be reduced by testing?” and “If the risk can be reduced, how much can testing reduce
it?” are asked. If the risk factors are well known, quantifi able, and under the control of
the project, it is likely that testing can reduce the probability of the risk occurring. Fully
controlled tests can be planned and completed. If, on the other hand, the risk factors are
not under control of the project or the risk factors are fuzzy (not well known or merely
qualitative), then testing does not have a fair chance to reduce the risk.
Testing objective 2: Perform testing to reduce identifi ed risks.
As we will see in subsequent chapters, test planning includes positive testing
(looking for things that work as required) and negative testing (looking for things that
break). The test planning effort emphasizes the risk areas so that the largest possible
percentage of the test schedule and effort (both positive testing and negative testing)
are dedicated to reducing that risk. Very seldom does testing completely eliminate a
risk because there are always more situations to test than time or resources to complete
the tests. One hundred percent testing is currently an unrealistic business expectation.
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