1. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.1 Chapter 17 Software Testing Strategies Slide Set to accompany Software Engineering: A Practitioner’s Approach, 7/e by Roger S. Pressman Slides copyright © 1996, 2001, 2005, 2009 by Roger S. Pressman For non-profit educational use only May be reproduced ONLY for student use at the university level when used in conjunction with Software Engineering: A Practitioner's Approach, 7/e. Any other reproduction or use is prohibited without the express written permission of the author. All copyright information MUST appear if these slides are posted on a website for student use.

2. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.2 Software Testing Testing is the process of exercising a program with the specific intent of finding errors prior to delivery to the end user.

3. Software Testing Software testing must be planned carefully to avoid wasting development time and resources. Testing begins “in the small” and progresses “to the large”. Initially individual components are tested and debugged. After the individual components have been tested and added to the system, integration testing takes place. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.3

4. Software Testing Once the full software product is completed, system testing is performed. The Test Specification document should be reviewed like all other software engineering work products. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.4

5. 5 What Testing Shows errors requirements conformance performance an indication of quality

6. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.6 Strategic Approach To perform effective testing, you should conduct effective technical reviews. By doing this, many errors will be eliminated before testing commences. Testing begins at the component level and works "outward" toward the integration of the entire computer- based system. Different testing techniques are appropriate for different software engineering approaches and at different points in time. Testing is conducted by the developer of the software and (for large projects) an independent test group. Testing and debugging are different activities, but debugging must be accommodated in any testing strategy.

7. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.7 V & V Verification refers to the set of tasks that ensure that software correctly implements a specific function. Validation refers to a different set of tasks that ensure that the software that has been built is traceable to customer requirements. Boehm [Boe81] states this another way: Verification: "Are we building the product right?" Validation: "Are we building the right product?"

8. Organizing the Software Testing Organizing for Software Testing The role of the Independent Test Group (ITG) is to remove the conflict of interest inherent when the builder is testing his or her own product. Misconceptions regarding the use of independent testing teams: The developer should do no testing at all These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.8

9. Organizing the Software Testing Software is tossed “over the wall” to people to test it mercilessly Testers are not involved with the project until it is time for it to be tested The developer and ITGC must work together throughout the software project to ensure that thorough tests will be conducted These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.9

10. 10 Who Tests the Software? developer independent tester Understands the system but, will test "gently" and, is driven by "delivery" Must learn about the system, but, will attempt to break it and, is driven by quality

11. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.11 Testing Strategy System engineering Analysis modeling Design modeling Code generation Unit test Integration test Validation test System test Refer to text book, page 453 for the diagram

12. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.12 Testing Strategy We begin by ‘testing-in-the-small’ and move toward ‘testing-in-the-large’ Unit Testing – makes heavy use of testing techniques that exercise specific control paths to detect errors in each software component individually Integration Testing – focuses on issues associated with verification and program construction as components begin interacting with one another

13. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.13 Testing Strategy Validation Testing – provides assurance that the software validation criteria (established during requirements analysis) meets all functional, behavioral, and performance requirements System Testing – verifies that all system elements mesh properly and that overall system function and performance has been achieved

14. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.14 Strategic Issues Specify product requirements in a quantifiable manner long before testing commences. State testing objectives explicitly. Understand the users of the software and develop a profile for each user category. Develop a testing plan that emphasizes “rapid cycle testing.” Build “robust” software that is designed to test itself Use effective technical reviews as a filter prior to testing Conduct technical reviews to assess the test strategy and test cases themselves. Develop a continuous improvement approach for the testing process.

15. Test Strategies for Conventional Software These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.15

16. Unit Testing Module interfaces are tested for proper information flow. Local data are examined to ensure that integrity is maintained. Boundary conditions are tested. Basis (independent) path are tested. All error handling paths should be tested. Drivers and/or stubs need to be developed to test incomplete software. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.16

17. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.17 Unit Testing module to be tested test cases results softwareengineer

18. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.18 Unit Testing interface local data structures boundary conditions independent paths error handling paths module to be tested test cases

19. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.19 Unit Test Environment Module stub stub driver RESULTS interface local data structures boundary conditions independent paths error handling paths test cases

20. Integration Testing Sandwich testing uses top-down tests for upper levels of program structure coupled with bottom-up tests for subordinate levels Testers should strive to indentify critical modules having the following requirements Overall plan for integration of software and the specific tests are documented in a test specification These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.20

21. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.21 Integration Testing Strategies  Top-down integration testing  Bottom-up integration testing  Regression testing  Smoke testing

22. Top Down Integration Main control module used as a test driver and stubs are substitutes for components directly subordinate to it. Subordinate stubs are replaced one at a time with real components (following the depth-first or breadth-first approach). Tests are conducted as each component is integrated. On completion of each set of tests and other stub is replaced with a real component. Regression testing may be used to ensure that new errors not introduced. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.22

23. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.23 Top Down Integration top module is tested with stubs stubs are replaced one at a time, "depth first" as new modules are integrated, some subset of tests is re-run A B C DE FG

24. Bottom-Up Integration Low level components are combined into clusters that perform a specific software function. A driver (control program) is written to coordinate test case input and output. The cluster is tested. Drivers are removed and clusters are combined moving upward in the program structure. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.24

25. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.25 Bottom-Up Integration drivers are replaced one at a time, "depth first" worker modules are grouped into builds and integrated A B C DE FG cluster

26. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.26 Sandwich Testing Top modules are tested with stubs Worker modules are grouped into builds and integrated A B C DE FG cluster

27. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.27 Regression Testing Regression testing is the re-execution of some subset of tests that have already been conducted to ensure that changes have not propagated unintended side effects Whenever software is corrected, some aspect of the software configuration (the program, its documentation, or the data that support it) is changed. Regression testing helps to ensure that changes (due to testing or for other reasons) do not introduce unintended behavior or additional errors. Regression testing may be conducted manually, by re- executing a subset of all test cases or using automated capture/playback tools.

28. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.28 Smoke Testing A common approach for creating “daily builds” for product software Smoke testing steps: Software components that have been translated into code are integrated into a “build.” A build includes all data files, libraries, reusable modules, and engineered components that are required to implement one or more product functions. A series of tests is designed to expose errors that will keep the build from properly performing its function. The intent should be to uncover “show stopper” errors that have the highest likelihood of throwing the software project behind schedule. The build is integrated with other builds and the entire product (in its current form) is smoke tested daily. The integration approach may be top down or bottom up.

29. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.29 High Order Testing Validation testing -focus is on software requirements Validation-Test Criteria Ensure that all functional requirements are satisfied, all behavior characteristics are achieved, all content is accurate and properly presented, all performance requirements are attained, documentation is correct, and usability and other requirements are met.

30. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.30 High Order Testing Configuration review/ audit Ensure that all elements of the software configuration have been properly developed, are cataloged, and have the necessary detail to strengthen the support activities.

31. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.31 High Order Testing Acceptance testing (alpha & beta testing) making sure the software works correctly for intended user in his or her normal work environment. Alpha test – version of the complete software is tested by customer under the supervision of the developer at the developer’s site Beta test – version of the complete software is tested by customer at his or her own site without the developer being present

32. High Order Testing System testing- focus is on system integration Recovery testing forces the software to fail in a variety of ways and verifies that recovery is properly performed Security testing verifies that protection mechanisms built into a system will, in fact, protect it from improper penetration These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.32

33. These slides are designed to accompany Software Engineering: A Practitioner’s Approach, 7/e (McGraw-Hill 2009). Slides copyright 2009 by Roger Pressman.33 High Order Testing Stress testing executes a system in a manner that demands resources in abnormal quantity, frequency, or volume Performance Testing test the run-time performance of software within the context of an integrated system Deployment Testing examines all installation procedures and specialized installation software that will be used by customers, and all documentation that will be used to introduce the software to end users.