Domain Testing: Divide and Conquer - Testing Education

e selected (Beizer, 1995; Collard, personal communication, July 22, 2003; Hamlet
& Taylor, 1990; Kaner, 2002b; Kaner & Bach, 2004; Myers, 1979). An example is
selection of test data lying on the boundaries of equivalence classes.
However, Hamlet and Taylor (1990) and Kaner and Bach (2004) have not
specifically described forming partitions or equivalence classes based on risks or
anticipated failures. Kaner and Bach (2004) identified specific tasks involved in the
risk-based domain testing approach:
The risk-based approach looks like this:
– Start by identifying a risk (a problem the program might have).
– Progress by discovering a class (an equivalence class) of tests that could
expose the problem.
– Question every test candidate
• What kind of problem do you have in mind?
• How will this test find that problem? (Is this in the right class?)
• What power does this test have against that kind of problem?
• Is there a more powerful test? A more powerful suite of tests? (Is this
the best representative?)
– Use the best representatives of the test classes to expose bugs. (part 5,
slide 3)
Hamlet and Taylor (1990) suggested development of fault-revealing
subdomains. They described the partition testing method to doing domain testing as
a failure-based approach. They also asserted that a good partition testing method
will help create subdomains, each of which is associated with a particular failure,
and that testing samples from a subdomain should enable detection of the
associated failure.
According to Kaner (2002b), risk-based domain testing leads to
development of powerful tests and optimal prioritization, assuming that correct
risks are first identified and then prioritized. The hazard with using the risk-based
approach is that testers might miss certain risks because they might not think they
are likely or just not be aware of them (Kaner, 2002b).
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