Orthogonal Array Software Testing

Orthogonal Array Testing: Taguchi Method

Orthogonal Array Testing is a statistical testing technique implemented by Taguchi. This method is extremely valuable for testing complex applications and e-comm products. The e-comm world presents interesting challenges for test case design and testing coverage. The black box testing technique will not adequately provide sufficient testing coverage. The underlining infrastructure connections between servers and legacy systems will not be understood by the black box testing team. A gray box testing team will have the necessary knowledge and combined with the power of statistical testing, an elaborate testing net can be set-up and implemented.

The theory -Orthogonal Array Testing (OAT) can be used to reduce the number of combinations and provide maximum coverage with a minimum number of test cases. OAT is an array of values in which each column represents a variable - factor that can take a certain set of values called levels. Each row represents a test case. In OAT, the factors are combined pair-wise rather than representing all possible combinations of factors and levels.

A simple example: Three Factors and Three Levels Array is shown in table 3.

Three Levels Array

Now given the example above, a tester would have to create 3³ or 27 test combinations as shown in table 4.

Number of test cases table

By assigning values for each factor and then extrapolating for combined pairing, our total number of test cases drops to nine from 27. This simple but effective technique maximizes the required testing coverage.

end explaining orthogonal arrays testing strategy and practice with example

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© January 2006 Alex Samurin geocities.com/xtremetesting/ ml>