Software Testing 3

1. Software Testing 3 Damian Gordon

2. Test Levels

3. Test Levels • Component Testing • Integration Testing • System Testing • Acceptance Testing

4. Test Levels • Component Testing

5. Test Levels • Component Testing • Also known as Unit Testing, Module Testing, and Program Testing

6. Test Levels • Component Testing • Searching for defects in, and verifies the functioning of software that are separately testable. • This testing can be done in isolation of other parts of the system, using stubs and drivers. A A Driver B Stub B

7. Test Levels • Component Testing • May include the testing of the functionality and specific non-functional characteristics such as resource behaviour, e.g. Memory leaks • Also Robustness testing or performance testing • Also structure testing, e.g. Decision coverage

8. Test Levels • Integration Testing

9. Test Levels • Integration Testing • Testing interfaces between components, as well as interactions to different parts of the system, such as an operating system, and a file system. • Component Integration Testing is testing interactions between components • System Integration Testing is testing the interaction of the developed system with other systems

10. Test Levels • Integration Testing • It’s generally better to integrate components to each other in groups, and then test that process, rather than a “big bang” integration when all discrete components are integrated simultaneously. • With the “big bang” approach, it is very difficult to trace the cause of failures to one specific component. • The opposite approach is integrating one component at a time, which can often be too time consuming.

11. Test Levels • Integration Testing • This incremental approach to integration leads to a number of possible approaches: • Top-Down: Test starts at the top, e.g. From the GUI or main menu • Bottom-up: One component at a time • Functional Incremental: Integration and testing on the basis of functionality

12. Test Levels • System Testing

13. Test Levels • System Testing • Looking at the behaviour of the whole system as defined by the scope of a development project. • It may include tests based on risks and/or requirements specification, business processes, use cases, or other high-level descriptions of system behaviour, interactions with the operating system, and system resources.

14. Test Levels • System Testing • It is most often the final testing on behalf of the development to verify that the system delivered meets the specification.

15. Test Levels • System Testing • It should include investigation of both the functional and non-functional requirements of the system • Typical non-functional tests include performance and reliability. • Typical functional tests include black-box testing.

16. Test Levels • System Testing • It must be undertaken in a controlled test environment, with software versions, testware, and test data. • The test environment needs to match the live environment as much as possible.

17. Test Levels • Acceptance Testing

18. Test Levels • Acceptance Testing • This is testing done by the customers/users, potentially as well as other stakeholders. • The goal of this testing is to establish confidence in the system, focussing on issues such as fit-for-purpose, and usability.

19. Test Levels • Acceptance Testing • Two types of acceptance testing: • The user acceptance test focuses mainly on functionality thereby validating the fitness-for-use of the system by the users. • The operational acceptance test validates whether the system meets the requirements for operation.

20. Test Levels • Acceptance Testing • Other types of acceptance testing: • Contract acceptance tests performed against a contract’s acceptance criteria for producing the software. • Compliance acceptance tests are preformed against regulations such as governmental, legal or safety regulations.

21. Test Levels • Acceptance Testing • If the software is intended for the mass market, customer testing is impractical, but feedback is needed, so it’s often done in a two stage process • The first is Alpha Testing, this takes place at the developers site, a cross-section of potential users are invited to use the system, and developers observe the users and note problems. • The second is Beta Testing, sends the system out to a cross-section of the users, who install it, and use it under real-world conditions. The users send records of incidents with the system to the development organisation where the defects are repaired.

22. Test Types

23. Test Types • Functional Testing • Non-functional Testing • Structural Testing • Confirmation and Regression Testing

24. Test Types • Functional Testing

25. Test Types • Functional Testing • The function of a system is “what it does”. • Typically described in requirements document, or in use cases. • Can be based on ISO 9124, but focusing on suitability, interoperability, security, accuracy, and compliance.

26. International Organization for Standardization • ISO is an international standard-setting body composed of representatives from various national standards organizations. Founded on February 23, 1947, the organization promulgates worldwide proprietary, industrial and commercial standards. It has its headquarters in Geneva, Switzerland.

27. Test Types • Functional Testing • Two types, Requirements-based testing and Business-process-based testing • Requirements-based testing use the functional specification to develop tests. • Business-process-based testing uses the knowledge of business processes.

28. Test Types • Non-Functional Testing

29. Test Types • Non-Functional Testing • Looking at quality characteristics, looking at how well something is being done, or how fast. • Includes things like, performance testing, load testing, stress testing, usability testing, maintainability testing, reliability testing, and portability testing.

30. Test Types • Non-Functional Testing • Can be based on ISO 9124, but focusing on reliability, usability, efficiency, maintainability, and portability.

31. Test Types • Structural Testing

32. Test Types • Structural Testing • Looking at the system architecture or structure of the system or component. • Often used as a way of measuring the thoroughness of the testing through coverage of a set of structural elements of coverage items.

33. Check if a number is odd or even START Read in A Does A/2 give a remainder? Print “It’s Odd” Print “It’s Even” No Yes END

34. Print out the biggest of two numbers START Read in A and B A>B? Print A Print B No Yes END

35. START Print out the biggest of three numbers Read in A, B and C A>C? A>B? B>C? No Yes Yes Yes No No Print A Print C Print B END

36. Print out the numbers 1 to 5 START A = 1 A = A + 1 Is A==6? No Print A Yes END

37. Test Types • Confirmation and Regression Testing

38. Test Types • Confirmation and Regression Testing • Testing changes to software, two general types: • Confirmation Testing • Regression Testing

39. Test Types • Confirmation and Regression Testing • Confirmation Testing • When a test fails and we determine the cause of the failure, once that defect is fixed, we need to rerun the test again to confirm that the error has been corrected. • It is important to rerun the test in the exact same way – same input, same data, and same environment.

40. Test Types • Confirmation and Regression Testing • Regression Testing • Testing to check if there hasn’t been any “unexpected side-effects” as a result of some change.