1. University of Southern California Center for Systems and Software Engineering Software Testing Supannika Koolmanojwong CSCI 577 Ref: Qi Li’s lectures 1

2. University of Southern California Center for Systems and Software Engineering 2 Outline Software Test in General Value-based Software Test

3. University of Southern California Center for Systems and Software Engineering Most Common Software problems  Incorrect calculation  Incorrect data edits & ineffective data edits  Incorrect matching and merging of data  Data searches that yields incorrect results  Incorrect processing of data relationship  Incorrect coding / implementation of business rules  Inadequate software performance 3

4. University of Southern California Center for Systems and Software Engineering  Confusing or misleading data  Software usability by end users & Obsolete Software  Inconsistent processing  Unreliable results or performance  Inadequate support of business needs  Incorrect or inadequate interfaces with other systems  Inadequate performance and security controls  Incorrect file handling 4

5. University of Southern California Center for Systems and Software Engineering Cost to fix faults Cost Definition DevelopmentPost Release 1* 1.5* to 6* 60* to 100* 5

6. University of Southern California Center for Systems and Software Engineering Objectives of testing Executing a program with the intent of finding an error. To check if the system meets the requirements and be executed successfully in the Intended environment. To check if the system is “ Fit for purpose”. To check if the system does what it is expected to do. 6

7. University of Southern California Center for Systems and Software Engineering Objectives of testing A good test case is one that has a probability of finding an as yet undiscovered error. A successful test is one that uncovers a yet undiscovered error. A good test is not redundant. A good test should be “best of breed”. A good test should neither be too simple nor too complex. 7

8. University of Southern California Center for Systems and Software Engineering Objective of a Software Tester Find bugs as early as possible and make sure they get fixed. To understand the application well. Study the functionality in detail to find where the bugs are likely to occur. Study the code to ensure that each and every line of code is tested. Create test cases in such a way that testing is done to uncover the hidden bugs and also ensure that the software is usable and reliable 8

9. University of Southern California Center for Systems and Software Engineering How do you know you are a good tester? Your love letters get returned to you marked up with red ink, highlighting your grammar and spelling mistakes. When you ask him how you look in a dress, he’ll actually tell you. He won’t help you change a broken light bulb because his job is simply to report and not to fix. He’ll keep bringing up old problems that you’ve since resolved just to make sure that they’re truly gone 9 Signs that you are dating a tester

10. University of Southern California Center for Systems and Software Engineering Software reviews, inspections and walkthroughs - Concerned with analysis of the static system representation to discover problems (static verification) Software testing with test cases - Concerned with exercising and observing product behaviour (dynamic verification) –The system is executed with test data and its operational behaviour is observed Static and Dynamic Verification 10

11. University of Southern California Center for Systems and Software Engineering Inspection Fagan Inspection –Process Planning  Overview meeting  Preparation  Inspection meeting  Rework  Follow-up –Inspection roles Author, Moderator, Reader, Recorder, Inspector –Inspection types Code review, peer review –Inspect Req Spec, Sys Arch, Programming, Test scripts 11

12. University of Southern California Center for Systems and Software Engineering Inspections and testing Inspections and testing are complementary and not opposing verification techniques Both should be used during the V & V process Inspections can check conformance with a specification but not conformance with the customer’s real requirements Inspections cannot check non-functional characteristics such as performance, usability, etc. 12

13. University of Southern California Center for Systems and Software Engineering Test data Inputs which have been devised to test the system Test cases Inputs to test the system and the predicted outputs from these inputs if the system operates according to its specification Test data and test cases 13

14. University of Southern California Center for Systems and Software Engineering Methods of testing Test to specification: –Black box –Data driven –Functional testing –Code is ignored: only use specification document to develop test cases Test to code: –Glass box/White box –Logic driven testing –Ignore specification and only examine the code. 14

15. University of Southern California Center for Systems and Software Engineering Types of Testing – (Jokes) Aggression Testing: If this doesn’t work, I’m gonna kill somebody. Compression Testing: [] Confession Testing: Okay, Okay, I did program that bug. Congressional Testing:Are you now, or have you ever been a bug? Depression Testing:If this doesn’t work, I’m gonna kill myself. Egression Testing: Uh-oh, a bug… I’m outta here. Digression Testing: Well, it works, but can I tell you about my truck… Expression Testing: #@%^&*!!!, a bug. Obsession Testing: I’ll find this bug if it’s the last thing I do. Oppression Testing: Test this now! Poission Testing: Alors! Regardez le poission! Repression Testing: It’s not a bug, it’s a feature. Secession Testing: The bug is dead! Long lives the bug! Suggestion Testing: Well, it works but wouldn’t it be better if… 15 Ref: netfunny.com

16. University of Southern California Center for Systems and Software Engineering Testing Levels Unit testing Integration testing System testing Acceptance testing 16

17. University of Southern California Center for Systems and Software Engineering Unit testing The most ‘micro’ scale of testing. Tests done on particular functions or code modules. Requires knowledge of the internal program design and code. Done by Programmers (not by testers). 17

18. University of Southern California Center for Systems and Software Engineering Integration Testing –Testing of combined parts of an application to determine their functional correctness. –‘Parts’ can be code modules individual applications client/server applications on a network. 18

19. University of Southern California Center for Systems and Software Engineering Systems Testing To test the co-existence of products and applications that are required to perform together in the production-like operational environment (hardware, software, network) To ensure that the system functions together with all the components of its environment as a total system To ensure that the system releases can be deployed in the current environment 19

20. University of Southern California Center for Systems and Software Engineering Acceptance Testing Objectives  To verify that the system meets the user requirements When  After System Testing Input  Business Needs & Detailed Requirements  Master Test Plan  User Acceptance Test Plan Output  User Acceptance Test report 20

21. University of Southern California Center for Systems and Software Engineering Load testing –Testing an application under heavy loads. –Eg. Testing of a web site under a range of loads to determine, when the system response time degraded or fails. 21

22. University of Southern California Center for Systems and Software Engineering Stress Testing –Testing under unusually heavy loads, heavy repetition of certain actions or inputs, input of large numerical values, large complex queries to a database etc. –Term often used interchangeably with ‘load’ and ‘performance’ testing. Performance testing –Testing how well an application complies to performance requirements. 22

23. University of Southern California Center for Systems and Software Engineering Alpha testing Testing done when development is nearing completion; minor design changes may still be made as a result of such testing. Beta-testing Testing when development and testing are essentially completed and final bugs and problems need to be found before release. 23

24. University of Southern California Center for Systems and Software Engineering Good Test Plans (1/2) Developed and Reviewed early. Clear, Complete and Specific Specifies tangible deliverables that can be inspected. Staff knows what to expect and when to expect it. 24

25. University of Southern California Center for Systems and Software Engineering Good Test Plans (2/2) Realistic quality levels for goals Includes time for planning Can be monitored and updated Includes user responsibilities Based on past experience Recognizes learning curves 25

26. University of Southern California Center for Systems and Software Engineering Test Cases Contents –Test plan reference id –Test case –Test condition –Expected behavior 26

27. University of Southern California Center for Systems and Software Engineering Good Test Cases Find Defects Have high probability of finding a new defect. Unambiguous tangible result that can be inspected. Repeatable and predictable. 27

28. University of Southern California Center for Systems and Software Engineering Good Test Cases Traceable to requirements or design documents Push systems to its limits Execution and tracking can be automated Do not mislead Feasible 28

29. University of Southern California Center for Systems and Software Engineering 29

30. University of Southern California Center for Systems and Software Engineering 30 Outline Software Test in General Value-based Software Test

31. University of Southern California Center for Systems and Software Engineering 31 Pareto 80-20 distribution of test case value [Bullock, 2000] Actual business value % of Value for Correct Customer Billing Customer Type 100 80 60 40 20 51015 Automated test generation tool - % of Value for Correct Customer Billing Customer Type 100 80 60 40 20 51015 Automated test generation tool - all tests have equal value * *Usual SwE assumption for all requirements, objects, defects, …

32. University of Southern California Center for Systems and Software Engineering Business Case for Value-Based Testing 32

33. University of Southern California Center for Systems and Software Engineering How can we compare the value of test cases ? How to prioritize test cases ? How to measure the value of test cases? 33

34. University of Southern California Center for Systems and Software Engineering Value-based Software Testing Framework- Feature Prioritization 34

35. University of Southern California Center for Systems and Software Engineering How much test is enough? 35 Li, Q., Yang, Y., Li, M., Wang, Q., Boehm, B. W. and Hu, C., Improving software testing process: feature prioritization to make winners of success-critical stakeholders. Journal of Software Maintenance and Evolution: Research and Practice, n/a. doi: 10.1002/smr.512

36. University of Southern California Center for Systems and Software Engineering Value-based Test Case Prioritization 36

37. University of Southern California Center for Systems and Software Engineering Value-based Test Order Logic 37 Value First: Test the one with the highest value. Dependency Second: If the test case with the highest value is not “Ready-to-Test”, which means at least one of the test cases in its Dependencies Set is “Not-Tested- Yet”. In such situation, prioritize the “Not-Tested-Yet” test cases according to “Value First” in this Dependencies Set and start to test until all test cases in the Dependencies Set are “Passed”. Then the test case with the highest value is “Ready-to-Test”. Shrink the prioritization set ASAP: Exclude the tested one out of the prioritization set.

38. University of Southern California Center for Systems and Software Engineering Value-based Test Order Logic 38

39. University of Southern California Center for Systems and Software Engineering Test Case Dependency Tree 39

40. University of Southern California Center for Systems and Software Engineering Accumulated Cost-Effectiveness (ACE) of Test 40

41. University of Southern California Center for Systems and Software Engineering Found bugs, then what? 41 http://softwaretestingandqa.blogspot.com/

42. University of Southern California Center for Systems and Software Engineering Developer: There is no I in TEAM Tester: We cannot spell BUGS without U 42

43. University of Southern California Center for Systems and Software Engineering Other information 43 CSCI599 Program Analysis & Software Testing Professor William Halfond Testing Tools: http://www.opensourcetesting.org/functional.php http://www.opensourcetesting.org/functional.php http://www.softwareqatest.com/qatweb1.html