  Higher Order Mutation (HOM) has been proposed to avoid equivalent mutants and
improve the scalability of mutation testing, but generating useful HOMs remain
an expensive search problem on its own. We propose a new approach to generate
Strongly Subsuming Higher Order Mutants (SSHOM) using a recently introduced
Causal Program Dependence Analysis (CPDA). CPDA itself is based on program
mutation, and provides quantitative estimation of how often a change of the
value of a program element will cause a value change of another program
element. Our SSHOM generation approach chooses pairs of program elements using
heuristics based on CPDA analysis, performs First Order Mutation to the chosen
pairs, and generates an HOM by combining two FOMs.
