Domain Testing: Divide and Conquer - Testing Education

in the correctness of the program. Code coverage-based testing methods like the
path analysis approach seem to give confidence in the program since they test all or
most portions of the code. This approach will probably miss all or some of the bugs
and issues that would have been revealed if the criterion for testing was to expose
all risky areas of the program and make the program fail in many interesting and
challenging ways.
2.01.02.02 Risk-Based Approach
There are other researchers who have talked about strategizing domain testing
effort based on risks. In other words, they described a fault-based or suspicion-
based approach to forming partitions (Beizer, 1995; Collard, personal
communication, July 22, 2003; Frankl et al., 1998; Gerrard & Thompson, 2002;
Hamlet, 2000; Hamlet & Taylor, 1990; Kaner, 2002b; Kaner & Bach, 2003; Myers,
1979; Podgurski & Yang, 1993; Whittaker & Jorgensen, 2002).
Gerrard and Thompson (2002) defined risk as: “A risk threatens one or
more of a project’s cardinal objectives and has an uncertain probability” (p. 14).
Kaner (2002b) characterized risk as: “Possibility of suffering loss or harm
(probability of an accident caused by a given hazard)” (slide 8). In other words, a
statement describing a risk is an assertion about how a program or system could
fail.
Collard said, “I often say in classes that a list of assumptions is a list of risk
factors with plans for how we are going to manage them. I also emphasize the
criticality of assumptions (how much does each one matter?), which is another way
of saying we need to prioritize based on risk” (personal communication, July 22,
2003).
Most of those who describe risk-based approaches to doing domain
testing do not specifically describe forming equivalence classes or partitions based
on risks, but their approach describes how risks should be identified and how test
data should be selected based on identified risks. Some researchers have described
how data points that represent the most risky areas in an equivalence class should
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