Understanding the Effects of Model Evolution Through Incremental Test Case Generation for UML-RT Models

Abstract

Model driven development (MDD) is on the rise in software engineering and no more so than in the realm of real-time and embedded systems. Being able to leverage the code generation and validation techniques made available through MDD is worth exploring, and is the focus of much academic and industrial research. However given the iterative nature of MDD, the natural evolution of models causes test case generation to occur multiple times throughout a software modeling project. Currently, the existing process of regenerating test cases for a modified model of a system can be costly, inefficient, and even redundant. The focus of this research was to achieve an improved understanding of the impact of typical model evolution steps on both the execution of the model and its test cases, and how this impact can be mitigated by reusing previously generated test cases. In this thesis we use existing techniques for symbolic execution and test case generation to perform an analysis on example models and determine how evolution affects model artifacts; these findings were then used to classify evolution steps based on their impact. From these classifications, we were able to determine exactly how to perform updates to existing symbolic execution trees and test suites in order to obtain the resulting test suites using minimal computational resources whenever possible. The approach was implemented in a software plugin, IncreTesCaGen, that is capable of incrementally generating test cases for a subset of UML-RT models by leveraging the existing testing artifacts (symbolic execution trees and test suites), as well as presenting additional analysis results to the user. Finally, we present the results of an initial evaluation of our tool, which provides insight into the tool’s performance, the effects of model evolution on execution and test case generation, as well as design tips to produce optimal models for evolution.