Domain Testing: Divide and Conquer - Testing Education

In the functional approach to doing domain testing, partitioning of the input
domain is done based on functions. Functional structures described in the
specification are studied and test data is developed around these structures
(Howden, 1986). The program at hand is analyzed to identify the functions
involved, the input variables involved and their constraints. According to Howden
(1981), identifying functions and selecting reliable test cases are two important
tasks in functional testing. Depending on what kind of function it is, the approach
to deriving a reliable test data set for the corresponding function will be different,
since each will have different kinds of errors associated with it (Howden, 1981).
One of the five types of functions identified by Howden (1981) based on
functional structure is the arithmetic relation function. “Arithmetic relation
functions are computed by expressions of the form E1 r E2, where E1 and E2 are
arithmetic expressions and r is one of the relational operators , =, =, = or ?” (p.
70).
According to Howden (1981), of the many errors that can be associated
with this type of function, a simple one is use of illegal or incorrect relation, which
in turn means use of an incorrect relational operator. To test for such an error, a
tester would consider two partitions. One corresponds to the set of test cases that
have the expressions related by the correct relational operator, and the other
partition consists of all test cases that have the expressions related by one of the
remaining sets of relational operators.
2.01.01.03 Combination of Black-Box and White-Box Testing
Approaches
As previously mentioned, there are also a few researchers who have talked about
leveraging the advantages of both white-box and black-box testing strategies and
described a combined approach to doing domain testing. Among the proponents of
such a combined approach have been Binder (1999), Chen et al. (2000),
Goodenough and Gerhart (1975), Hamlet and Taylor (1990), Howden (1980a),
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