Fragment class analysis for testing of polymorphism in Java software

Adequate testing of polymorphism in object-oriented software requires coverage of all possible bindings of receiver classes and target methods at call sites. Tools that measure this coverage need to use class analysis to compute the coverage requirements. However, traditional whole-program class analysis cannot be used when testing partial programs. To solve this problem, we present a general approach for adapting whole-program class analyses to operate on program fragments. Furthermore, since analysis precision is critical for coverage tools, we provide precision measurements for several analyses by determining which of the computed coverage requirements are actually feasible. Our work enables the use of whole-program class analyses for testing of polymorphism in partial programs, and identifies analyses that compute precise coverage requirements and therefore are good candidates for use in coverage tools.