Data-Flow Testing in the Large

Data-flow (DF) testing was introduced more than thirty years ago aiming at extensively evaluating a program structure. It requires tests that traverse a path in which the definition of a variable and its subsequent use, i.e., a definition-use association (dua), is exercised. While control-flow testing tools have being able to tackle big systems-large and long running programs, DF testing tools have failed to do so. This situation is in part due to the costs associated with tracking duas at run-time. Recently, an algorithm, called Bitwise Algorithm (BA), which uses bit vectors and bitwise operations for tracking intra-procedural duas at run-time, was proposed. This paper presents the implementation of BA for programs compiled into bytecodes. Previous approaches were able to deal with small to medium size programs with high penalties in terms of execution and memory. Our experimental results show that by using BA we are able to tackle large systems with more than 200 KLOCs and 300K required duas. Furthermore, for several programs the execution penalty was comparable with that imposed by a popular control-flow testing tool.