“Combinatorial testing can detect hard-to-find software faults more efficiently than manual test case selection methods.”

Developers of large data-intensive software often notice an interesting—though not surprising—phenomenon: When usage of an application jumps dramatically, components that have operated for months without trouble suddenly develop previously undetected errors. For example, newly added customers may have account records with an oddball combination of values that have not been seen before. Some of these rare combinations trigger faults that have escaped previous testing and extensive use. Alternatively, the application may have been installed on a different OS-hardware-DBMS-networking platform. Combinatorial testing can help detect problems like this early in the testing life cycle. The key insight underlying t-way combinatorial testing is that not every parameter contributes to every fault and many faults are caused by interactions between a relatively small number of parameters.