Automatic Extraction of Object-Oriented Observer Abstractions from Unit-Test Executions

  • Tao Xie
  • David Notkin
Part of the Lecture Notes in Computer Science book series (LNCS, volume 3308)


Unit testing has become a common step in software development. Although manually created unit tests are valuable, they are often insufficient; therefore, programmers can use an automatic unit-test-generation tool to produce a large number of additional tests for a class. However, without a priori specifications, programmers cannot practically inspect the execution of each automatically generated test. In this paper, we develop the observer abstraction approach for automatically extracting object-state-transition information of a class from unit-test executions, without requiring a priori specifications. Given a class and a set of its initial tests generated by a third-party tool, we generate new tests to augment the initial tests and produce the abstract state of an object based on the return values of a set of observers (public methods with non-void returns) invoked on the object. From the executions of both the new and initial tests, we automatically extract observer abstractions, each of which is an object state machine (OSM): a state in the OSM represents an abstract state and a transition in the OSM represents method calls. We have implemented the Obstra tool for the approach and have applied the approach on complex data structures; our experiences suggest that this approach provides useful object-state-transition information for programmers to inspect unit-test executions effectively.


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  1. 1.
    Ammons, G., Bodik, R., Larus, J.R.: Mining specifications. In: Proc. the 29th ACM SIGPLAN-SIGACT Symposium on Principles of Programming Languages, pp. 4–16 (2002)Google Scholar
  2. 2.
    Arnold, K., Gosling, J., Holmes, D.: The Java Programming Language. Addison-Wesley Longman Publishing Co. Inc., Amsterdam (2000)Google Scholar
  3. 3.
    Ball, T., Majumdar, R., Millstein, T., Rajamani, S.K.: Automatic predicate abstraction of C programs. In: Proc. the ACM SIGPLAN 2001 Conference on Programming Language Design and Implementation, pp. 203–213 (2001)Google Scholar
  4. 4.
    Boyapati, C., Khurshid, S., Marinov, D.: Korat: automated testing based on Java predicates. In: Proc. the International Symposium on Software Testing and Analysis, pp. 123–133 (2002)Google Scholar
  5. 5.
    Csallner, C., Smaragdakis, Y.: JCrasher documents. Online manual (December 2003)Google Scholar
  6. 6.
    Dahm, M., van Zyl, J.: Byte Code Engineering Library (April 2003),
  7. 7.
    Ernst, M.D., Cockrell, J., Griswold, W.G., Notkin, D.: Dynamically discovering likely program invariants to support program evolution. IEEE Trans. Softw. Eng. 27(2), 99–123 (2001)CrossRefGoogle Scholar
  8. 8.
    Gansner, E.R., North, S.C.: An open graph visualization system and its applications to software engineering. Software: Practice and Experience 30(11), 1203–1233 (2000)MATHCrossRefGoogle Scholar
  9. 9.
    Graf, S., Saidi, H.: Construction of abstract state graphs with PVS. In: Proc. the 9th International Conference on Computer Aided Verification, pp. 72–83 (1997)Google Scholar
  10. 10.
    Grieskamp, W., Gurevich, Y., Schulte, W., Veanes, M.: Generating finite state machines from abstract state machines. In: Proc. the International Symposium on Software Testing and Analysis, pp. 112–122 (2002)Google Scholar
  11. 11.
    Gupta, N., Mathur, A.P., Soffa, M.L.: Automated test data generation using an iterative relaxation method. In: Proc. the 6th ACM SIGSOFT International Symposium on Foundations of Software Engineering, pp. 231–244 (1998)Google Scholar
  12. 12.
    Henkel, J., Diwan, A.: Discovering algebraic specifications from Java classes. In: Proc. the 17th European Conference on Object-Oriented Programming, pp. 431–456 (2003)Google Scholar
  13. 13.
    JUnit (2003),
  14. 14.
    Kung, D., Suchak, N., Gao, J., Hsia, P.: On object state testing. In: Proc. the 18th Annual International Computer Software and Applications Conference, pp. 222–227 (1994)Google Scholar
  15. 15.
    Lee, D., Yannakakis, M.: Principles and methods of testing finite state machines - A survey. In: Proc. The IEEE, vol. 84, August 1996, pp. 1090–1123 (1996)Google Scholar
  16. 16.
    Liskov, B., Guttag, J.: Program Development in Java: Abstraction, Specification, and Object-Oriented Design. Addison-Wesley, Reading (2000)Google Scholar
  17. 17.
    Nguyen, D.: Design patterns for data structures. In: Proc. the 29th SIGCSE Technical Symposium on Computer Science Education, pp. 336–340 (1998)Google Scholar
  18. 18.
    Parasoft. Jtest manuals version 4.5. Online manual (April 2003),
  19. 19.
    Sun Microsystems. Java 2 Platform, Standard Edition, v 1.4.2, API Specification. Online documentation (November 2003),
  20. 20.
    Turner, C.D., Robson, D.J.: The state-based testing of object-oriented programs. In: Proc. the Conference on Software Maintenance, pp. 302–310 (1993)Google Scholar
  21. 21.
    Whaley, J., Martin, M.C., Lam, M.S.: Automatic extraction of object-oriented component interfaces. In: Proc. the International Symposium on Software Testing and Analysis, pp. 218–228 (2002)Google Scholar
  22. 22.
    Xie, T., Marinov, D., Notkin, D.: Improving generation of object-oriented test suites by avoiding redundant tests. Technical Report UW-CSE-04-01-05, University of Washington Department of Computer Science and Engineering, Seattle, WA (January 2004)Google Scholar
  23. 23.
    Xie, T., Marinov, D., Notkin, D.: Rostra: A framework for detecting redundant object-oriented unit tests. In: Proc. 19th IEEE International Conference on Automated Software Engineering (2004)Google Scholar
  24. 24.
    Xie, T., Notkin, D.: Mutually enhancing test generation and specification inference. In: Petrenko, A., Ulrich, A. (eds.) FATES 2003. LNCS, vol. 2931, pp. 60–69. Springer, Heidelberg (2004)CrossRefGoogle Scholar
  25. 25.
    Xie, T., Notkin, D.: Tool-assisted unit test selection based on operational violations. In: Proc. 18th IEEE International Conference on Automated Software Engineering, pp. 40–48 (2003)Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2004

Authors and Affiliations

  • Tao Xie
    • 1
  • David Notkin
    • 1
  1. 1.Department of Computer Science & EngineeringUniversity of WashingtonSeattleUSA

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