Combination Testing:
Testing two or more variables in combination with each other. Combination testing is important but many testers don't study enough of it. Most benefits provided by the program are based on the interactions of many variables. If you don't vary them jointly in your tests you will miss errors that are triggered by difficult combinations rather than difficult individual values. Combination testing involves testing several variables together. The first critical problem of combination testing is the number of test cases. Imagine testing three variables together, when each variable has 100 possible values the number of possible tests of variable 1 with variable 2 with variable 3 is 100x100x100=1000000 test cases. Reducing the number of test cases is critical priority.
Some useful stuff on Combination Testing:
Notes for the Workshop on Combination Testing by Cem Kaner
Combination Testing
Examples of Combination (Multi-Variable) Testing
Combination Testing
An Evaluation of Combination Strategies for Test Case Selection
Combination Testing
In this below PPT you can understand rationale and basic approach for systematic combinatorial testing, Learn how to apply some representative combinatorial approaches- Category-partition testing, Pairwise combination testing and Catalog-based testing, Understand key differences and similarities among the approaches etc.
Combinatorial Testing
Test teams are often faced with an enormous number of test scenarios, each of which has the potential to break software. No one expects you to test all combinations; it would take a lifetime to do that. And so the essential question remains: How do you test effectively? This session offers you tips for choosing your tests wisely. This way, you maximize coverage using few tests. Bernie Berger presents examples of all-pairs test case sets using both discrete and non-discrete values. He also shows you how to organize the all-pairs test case sets, especially when values are conditional.
Efficient Testing with All-Pairs
Combination Testing Methods:
Pairwise Testing / All Pair Testing
Category-Partition Method
Catalog Based Testing