1. Ch 22 Verification and Validation
Verification: "Are we building the product right.”
The software must conform to its specification
This is usually contractual
Validation: "Are we building the right product"
The software should do what the user requires
This is good business
Points on weather:
Architecture suggests objects: weather station, map db, map, weather data.
No object for WMS. This is the control. I might include a WMS top object
Aggregation puts WMS at top. This is controller, asking for and proc data. I might do this early
hw: object convenient
Service usage: interaction diagrams test dataflow. Relate to uc?
What is the next step? (Interface which gets closer to data structures and then fill in bodies)
14.4
14.5:
The weather station is now responsible for sending data and needs an active process
Fig loses upper left pieces
14.6a
Diary: one for each person
Appointment
User: has a diary
Schedule?

2. Static and dynamic V&V
Static: Analyze the static system representations to discover problems.
This can head off problems early
Dynamic: Test and observe product behavior. The most widely used.

3. Types of testing (dynamic)
Validation testing
intended to show that the software meets its requirements
successful tests show a requirement has been properly implemented
Defect testing
designed to discover system defects
a successful test reveals the presence of defects
covered in Chapter 23

4. V& V Goals Confidence depends on
establish confidence that the software is fit for its purpose
this does NOT mean completely free of defects
rather, it must be good enough for its intended use
Confidence depends on
software function (how critical the software is )
user expectations (certain kinds of software may have low expectations )
Marketing environment (getting a product to market early may be more important than finding defects)

5. How would testing approaches differ for
CS 132 assignment
Wells on-line application form
Amazon’s e-commerce site
MH53J avionics system
Pacemaker

6. Testing versus debugging
Defect testing and debugging are distinct
V&V (testing): establish the existence of defects
Debugging: locate and repair defects

7. 22.1 V & V planning

8. The software test plan

9. Examples of acceptance tests:
User tests
add a new user
send a message
WIM administration tests
Reviewing traffic reports – might be performed after the send message test to see if it is documented

10. 19.2 Software inspections (static)
What do you do to check out code during development?
Inspections: examining code to discover anomalies/defects
Complementary to testing
Intended for defect detection (not correction)
Defects may be
logical errors
code anomalies that might indicate an erroneous condition (e.g. an uninitialized variable)
non-compliance with standards
Very effective for discovering errors
Does not require system execution so may be used early
May be applied to any representation of the system (requirements, design, configuration data, test data)

11. Inspection Preconditions: Teams a precise specification
team members familiar with organization standards
syntactically correct code
an error checklist
management accepting that inspection will increase costs early on
management who does not use inspections for staff appraisal
Teams
author of the code being inspected
inspectors who find errors, omissions and inconsistencies
reader who reads the code to the team
moderator who chairs the meeting and notes errors
scribe, other team members

12. Inspection Process Checklists
list of common errors to guide the inspection
the list is programming language dependent
what would you include?

13. Inspection checks 1

14. Inspection checks 2

15. Inspection rate 500 statements/hour during overview
125 source statement/hour during individual preparation
statements/hour can be inspected
Inspection is therefore expensive
Inspecting 500 lines costs about 40 person/hours effort ~$3000

16. 22.3 Automated static analysis
Static analyzers: software tools for source text processing
Parse the program text and try to discover potential errors
Very effective as an aid to inspections
A supplement to but not a replacement
Valuable for a languages with weak typing checking (C)
Less necessary for languages with strong type checking
How does Visual C++ do here?

17. Static analysis checks

18. 22.4.1 Cleanroom software development
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