Different testers have different understandings of the role and mission of software testing; of the approaches, methods, and techniques to use during testing.

1. Schools of
Software Testing

2. - Different testers have different
understandings of the role and mission of
software testing.
- Different testers have different
understandings of the aproaches, methods
and techniques to use during testing.
Introduction

3. Origins
- Bret Pettichord, The Four Schools of
Software Testing.
- Presentation at the Workshop on
Teaching Software Testing, Melbourne,
FL, 2003.
- This was an important attempt to
understand testing cultures and their
principles.

4. The members share fundamental beliefs:
- use similar vocabulary,
- approach similar tequiques,
- refer the same books or papers,
- decide that X is an example of good work or an
example of weak work,
- train appropriate skills,
- have the same value of the quality of the product
under the testing etc.
What is School?

5. Four Schools of Software
Testing
- Factory School
(Routine School)
- Context-Driven
School
- Analytical
School
- Quality Assurance
School
(Control School)

6. - Software is a logical artifact
- Testing is a branch of
CS/Mathematics
- Testing techniques must have a
logical “one right answer”
- Testing is technical
Analytical School :
Core Benefits

7. - Key question:
Which techniques should we use?
- Key Implications:
● Precise and detailed specifications are a
prerequisite for testing,
● Testers verify that the software behavior
conforms to its specification
Analytical School :
Key Points

8. - Most Prevalent: high-reliability industry,
telecom, space projects
- Authors: Boris Beizer, Paul Jorgensen,
Robert V. Binder, John D. Musa
- Creed: formulas and flowcharts and state
diagrams will save us.
Analytical School :
People

9. - Software development is a project
- Testing is a measure of progress
- Testing must be managed
- Predictable, repeatable, planned
- Testing must be cost-effective
- Low-skilled workers require direction
- Testing has rules
Factory School :
Core Benefits

10. - Key question:
What metrics should we use?
- Key Implications:
● Make sure that every requirement has been
tested,
● Requires clear boundaries between testing
and other activities (start/stop criteria),
● Encourages industry testing standards,
“best practices,” and certification
Factory School :
Key Points

11. - Most Prevalent: government
projects
- Authors: Rex Black, Dorothy
Graham
- Creed: lots of planning,
scripting, and other paperwork
will save us.
Factory School :
People

12. - Software quality requires discipline
- Testing determines whether development
processes are being followed
- Testers may need to police developers to
follow the rules
- Testers have to protect users from bad
software
Quality Assurance School :
Core Benefits

13. - Key Question:
Are we following a good process?
- Key Implications:
● The software isn’t ready until QA says it’s
ready
● Prefer “Quality Assurance” over “Testing”
● Testing is a stepping stone to “process
improvement”
Quality Assurance School :
Key Points

14. - Most Prevalent: large bureaucracies,
organizations under stress
- Authors: Alka Jarvis
- Creed: testers are the gatekeepers − telling
other people how to do their jobs will save us.
Quality Assurance School:
People

15. - Software is created by people
- People set the context
- Testing finds bugs
- A bug is anything that could bug a
stakeholder
- Testing provides information to the project
- Testing is a skilled, mental activity
- Testing is multidisciplinary
Context-Driven School :
Core Benefits

16. - Key Question: What tests would be most
valuable right now?
- Key Implications:
● Expect changes
● Adapt testing plans based on test results
● Effectiveness of test strategies can only be
determined with field research
● Focus on skill over practice
Context-Driven School :
Key Points

17. - Most Prominent: commercial, market-driven
software
- Authors: Cem Kaner, James Bach, Michael Bolton
- Creed: our skills, our ability to think critically, and
our ability to choose practices appropriate to serving
the testing mission, will help us (not save us) − the
other schools may have valuable things to teach us −
nothing will guarantee perfect testing.
Context-Driven School:
People

18. - Factory School
(Routine School)
A managed process
- Context-Driven
School
A branch of development
- Analytical
School
A branch of CS and
mathematics
- Quality Assurance
School
A branch of software
quality assurance
Comparison:
What is Testing?

19. - Factory School
(Routine School)
Do it if requested by
management
- Context-Driven
School
Definitely do it.
Usability bugs are bugs
- Analytical
School
Not a form of testing.
Outside the testing
skill set
- Quality Assurance
School
Reluctant. Hard to prove
noncompliance
Comparison:
Usability Testing?

20. - Factory School
(Routine School)
Some kind of spec is
necessary
- Context-Driven
School
Do what you can to be useful.
Ask questions. Dig up “hidden”
specs
- Analytical
School
Impossible
- Quality Assurance
School
Force developers to follow
the process
Comparison:
Testing Without Specs?

21. References:
- http://kaner.com/?p=15 - Cem Kaner
- http://www.satisfice.com/blog/archives/134 - James Bach
- http://www.testingeducation.org/conference/wtst_pettichord_FSofST2.pdf
- Bret Petichord
- http://www.developsense.com/blog/2008/11/theres-been-lot-of-controvers
y-on/ - Michael Bolton
- https://ukalf.com/index.php?q=node/131 - Poul Gerrard

22. Thank you.
Questions?