1. Software Quality Assurance Lecture #4 By: Faraz Ahmed

2. Contents

3. Projects 1. Ecommerce Website 2. Inventory Management System 3. Point of Sale system 4. Employee Management System 5. Patient Management System

4. Pareto Principle 0 80% of the problems stem from 20% of causes 0 This applies to many aspects of life such as sales. Richest 20% Income 82.70%

5. Walkthroughs 0 Informal meetings 0 Peer reviews 0 Code Reviews 0 Advantages 0 Exchanging ideas 0 Getting team on board

6. Software Inspections 0 After the popular Fagan Inspection 0 Planning: 0 Overview: Focus and role definition 0 Preparation: Reviewing of roles 0 Inspection Meeting: Finding of defect 0 Rework 0 Follow-up: moderator verifies.

7. Roles in inspections 0 Moderator 0 Author/Designer/Coder 0 Tester (many people possible)

8. Defect 0 An error, flaw, mistake, failure, or fault in a computer program that prevents it from behaving in the intended way.

9. Defect Management Process 0 A multi-step approach to defect management. 0 Defects cannot be removed altogether 0 But we can suppress their negative effect to some extent.

10. Defect Management Process (contd.) 0 Defect Prevention 0 Deliverable baseline 0 Defect Discovery 0 Defect Resolution 0 Process Improvement 0 Management Reporting

11. Defect Prevention 0 Identify ‘critical’ risks 0 Estimate expected impact 0 Minimize expected impact

12. Identify Risks 0 Risks that could effect the successful completion of project. 0 E.g. 0 Missing a key requirement 0 A key component not working as expected 0 Technology not available (e.g. as in avatar) 0 Only those risks that are specific to project

13. Estimate Expected Impact 0 Two important aspects: Probability and Cost 0 E(stimate) = P(robability) x I(mpact) 0 The impact is only low when there are reasons justifying it.

14. Minimize Impact 0 The impact becomes severe if it is left for long. 0 Eliminate the Risk 0 Reduce the Probability of a Risk Becoming a Problem: Most strategies will fall into this category. Inspections and testing are examples of approaches that reduce, but do not eliminate, the probability of problems. 0 Reduce the Impact if there is a Problem: In some situations, the risk can not be eliminated, and even when the probability of a problem is low, the expected impact is high.

15. Deliverable Baselined 0 Baselined after reaching a milestone/increment 0 Changes are more expensive. 0 Activities 0 Identify key deliverables 0 Define standards for each deliverable

16. Defect Discovery 0 A defect is only realized once the software engineers acknowledge a problem 0 This mechanism of reporting should be available reducing the time. 0 Activities 0 Find Defect 0 Report Defect 0 Acknowledge Defect

17. Find Defect 0 Ways 0 During development ( SQA, inspections, testing etc) 0 Three categories 0 Static Techniques: Testing without running software. E.g. Code review. 0 Dynamic Techniques: Physical execution. E.g. test cases, unit tests. 0 Operational Techniques: found in a deliverable

18. Fact Finding! 0 When Shell Oil followed the inspection process, they recorded the following results: 0 For each hour spent in the inspection process, ten hours were saved! 0 Their defect removal efficiency with inspections was 95- 97% versus roughly 60% for systems that did not use inspections.

19. Report Defect 0 Easier to report within team 0 What happens when you are a user? 0 Developers do not accept mistake 0 Users not sure whether it is really a problem or CHANGE 0 A process is needed to facilitate this understanding.

20. Acknowledge Defects 0 One hurdle is to replicate the user environment. 0 Trap events as they occur! 0 May lead to friction and might need arbitration!

21. Defect Resolution Process 0 After a valid defect has been acknowledged 0 Prioritize Risk: ‘Age’, priority and actions to be taken while fixing. 0 Schedule Fix and Fix defect: In additions, artifacts might be updated. 0 Report resolution

22. Report Resolution 0 The nature of the fix 0 When the fix would be released 0 How the fix would be released.

23. Process Improvement 0 The retrospective aspect of the whole process. 0 If this defect has gotten so far undetected, can their be others? 0 How to minimize a similar defect way before?

24. Communicating 0 Defect rates, defect trends, types of defects, failure costs. 0 Changes in timeline 0 Negotiations with client? 0 For forecasting new projects.

25. QUIZ!! 0 What are non-goals? 0 In “Joel on Software”, what were the recommendations for writing a functional spec? Mention atleast one.

26. Thank you for showing up early!