Domain Testing: Divide and Conquer - Testing Education

partition testing beats random testing by an insignificant amount, then the
effectiveness of proportional partition testing when compared with random testing
is questionable not only in terms of cost (overhead of generation of thousands of
test cases) but also in terms of how effective it is in detecting failures.
Ntafos (1998) also pointed out that partition testing strategies that rely on
random selection of representatives from subdomains that are considered
homogenous are ineffective in finding certain errors when compared with testing
strategies that involve knowledge-based selection of test cases. These would
include boundary values in domain testing, selection of test cases based on
anticipated failures or risk-prone areas in case of risk-based approach and selection
of test cases based on important features or functions of a software. He further
argued that forming perfectly homogeneous subdomains has been practically
impossible, so random selection of test cases from so-called homogeneous
subdomains might not be a great idea after all.
2.02.03 Risk-Based Selection
Here we select test cases based on risk. Section 2.01.02.02 discussed how risk-
based testing strategies determine risks and select test cases based on these risks.
One of the most familiar risk-based test case selection strategies is called boundary
values analysis. Jorgensen (2002) also identified certain other risk-based test
selection strategies, such as special value testing and worst case testing.
2.02.03.01 Boundary Value Analysis
“Experience shows that test cases that explore boundary conditions have a higher
payoff than test cases that do not. Boundary conditions are those situations directly
on, above, and beneath the edges of input equivalence classes and output
equivalence classes” (Myers, 1979, p. 50).
“A boundary describes a change-point for a program. The program is
supposed to work one way for anything on one side of the boundary. It does
something different for anything on the other side” (Kaner et al., 1999, p. 399).
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