1. Software Quality & Testing
Unit 1

2. Lessons from the past

3. McDonalds Free MP3 Player
Japan
Promotional offer by Coca Cola
10,000 infected MP3 players
10 free songs
QQPass Trojan

4. Mars Orbiter Priority inversion bug

5. NASA Mars Climate Orbiter
speeding through space and speaking to NASA in metric. But the engineers on the ground were replying in non-metric English.

6. Denver Airport’s Baggage Handling System
BAE Automated Systems

7. A 380 – The Largest Passenger Airliner

8. A380 Delays A380 is being developed in four countries
Spain
Germany
France UK
The whole program delayed by 2 years because of the configuration problems of the wiring software.
According to the reports on October 2006, cost of the consequent two-year delay to Airbus is estimated to be 4.8 billion euros.

9. Is testing important?

10. Bug vs fault vs error vs failure

11. Cost of Software Bugs
WASHINGTON (COMPUTERWORLD) - Software bugs are costing the U.S. economy an estimated $59.5 billion each year, with more than half of the cost borne by end users and the remainder by developers and vendors, according to a new federal study. Improvements in testing could reduce this cost by about a third, or $22.5 billion, but it won't eliminate all software errors, the study said. Of the total $59.5 billion cost, users incurred 64% of the cost and developers 36%.

12. What is Quality?

13. Software Quality Assurance : Definitions
“The function of software quality that assures that the standards, processes, and procedures are appropriate for the project and are correctly implemented.”

14. Quality is conformance to specifications (British Defense Industries Quality Assurance Panel)

15. Quality is conformance to requirements (Philip Crosby)

16. Quality is fitness for purpose or use (Juran)

17. Quality is a predictable degree of uniformity and dependability, at low cost and suited to the market (Edward Deming)

18. Quality is synonymous with customer needs and expectations (R J Mortiboys)

19. Quality is meeting the (stated) requirements of the customer- now and in the future (Mike Robinson)

20. Quality is the total composite product and service characteristics of marketing, engineering, manufacturing and maintenance through which the product and service in use will meet the expectations by the customer (Armand Feigenbaum)

21. Totality of characteristics of an entity that bear on its ability to satisfy stated and implied needs (ISO 8402 : 1994)

22. … implied needs must be turned into requirements … PMBOK

23. What is Software Quality?
many aspects
Popular View
Intangible
“I know it when I see it”
Subjective NOT objective / discreet
E.g

24. What is Software Quality?
Professional View
it is a moral and legal
“best practices”
product quality must be measurable in some way
Product quality
conformance to requirements
fitness for use
freedom from errors and failures
customer satisfaction

25. Quality Parameters External Quality Parameters
Correctness
Usability
Efficiency
Reliability
Integrity
Adaptability
Accuracy
Robustness
Internal Quality Parameters
Maintainability
Flexibility
Portability
Reusability
Readability
Testability
Understandability

26. Effect of Quality Attributes

27. Software Quality Principle
Principle 1: Know What You Are Doing
We normally address this by following a software process with regular milestones, planning, scheduling, reporting and tracking procedures

28. Software Quality Principle
Principle 2: Know What You Should be Doing

29. Software Quality Principle
Principle 3: Know How to Measure the Difference
Measurement?
formal methods
testing
inspection
metrics

30. Formal Methods What would you need? Formal methods include
formal verification
abstract interpretation
state modeling
other mathematical methods
quality assurance
E.g
What would you need?

31. Software Testing : Definition
“The process of devising a set of inputs to a given piece of software that will cause the software to exercise some portion of its code.
The developer of the software can then check that the results produced by the software are in accord with his or her expectations.”

32. A Testing Cycle Subjective to organization Requirements Analysis:
Design Analysis:
Test Planning:
Test Development:
Test Execution:
Test Reporting:
Retesting the Defects

33. Question remains the same, “why would I need to test my software?”

34. Some Software Testing Objectives
Find as many defects as possible.
Find important problems fast.
Assess perceived quality risks.
Advise about perceived project risks.
Advise about perceived quality.
Certify to a given standard.
Assess conformance to a specification (requirements, design, or product claims).

35. Testing Testing?? Types of Testing Acceptance testing,
Functionality Testing
Interface testing
Regression testing
Unit Testing
GUI Testing
Structural Testing
And many more

36. Inspection and Metrics

37. Effectiveness of Removing Defects