It is impractical in many situations for testers to test every possible permutation of software tests.

In this video Justin Hunter, the founder of Hexawise, explains how combinatorial explosions impact software testing. He explains how to quickly calculate the total possible number of permutations exist in simplified systems under test using several examples.

The video ends with a reference to a continuation of this discussion in the next video: How Many Pairwise Tests Required (In the Face of Combinatorial Explosions).

Related: Combinatorial Testing, The Quadrant of Massive Efficiency Gains – Mind Maps: What, Why and How – Combinatorial Testing for Software