?????%20(Verification%20and%20Validation)

1
?????(Verification and Validation)

• ??????????????

2
??

• ???????(verification)???(validation),??????????
• ????????(program inspections process)???VV????
• ??????(static analysis)?????????
• ????(cleanroom)??????

3
??

1. ???????(verification and validation planning)
2. ????(software inspection)
3. ???????(automated static analysis)
4. ??????(cleanroom software development)

4
????????

• ??(verification)
• ??????????(are we building the product right)
• ??????????
• ??(validation)
• ????????????(are we building the right product)
• ???????????????

5
VV??

• ????????????(life-cycle process)V
  V??????????????????
• ??????
• ????????(defects)
• ?????????????(operational situation)

6
???????(Static and Dynamic Verification)

• ????(software inspections)
• ???????????(????)
• ????????????(tool-based document and code
  analysis)???
• ????
• ??????????(????)
• ?????????????????(operational behavior)

7
?????VV
8
????

• ??????????,?????????(end user),???????????

9
????(Testability)

• ????(operability)
• ?????(operate cleanly)
• ????(observability)
• ??????????????
• ????(controlability)
• ????????????????

10

• ????(decomposability)
• ?????????(testing can be targeted)
• ???(simplicity)
• ??????????????
• ???(stability)
• ????,???????
• ????(understandability)
• ?????????

11
????(Program Testing)

• ???????????????
• ??????????????????
• ????????(non-functional)???????(validation
  technique)
• ??????(static verification)????,??????VV????(cove
  rage)

12
????

• ????(defect testing)
• ???????????
• ???????????????????
• ????(statistical testing)
• ???????????????
• ???????(reliability estimation)

13
V V ???

• ??(verification)???(validation)?????????????
• ???????????(free of defects)
• ????????????????????(intended use),????????(type
  of use)????????????(degree of confidence)

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V V???

• ?????????????(user expectation)?????(marketing
  environment)??
• ????
• ???????(level of confidence)?????????????
• ?????
• ????????????????
• ????
• ?????????????????????

15
?????(Testing and Debugging)

• ?????????????
• ??(verification)???(validation)???????????
• ??(debugging)???(locating)????????(repairing)??
• ?????????(program behavior)????(formulating a
  hypothesis),??????????????

16
????(Debugging Process)
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1. V V ???

• ???????????????????
• ?????????????
• ????????(static verification)???(testing)?????
• ?????????????????(define standards for testing
  process),????????(product test)

18
???????(V-model of Development)
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????????(The Structure of a Software Test Plan)

• ????(testing process)
• ????(requirement traceability)
• ????(tested items)
• ????(testing schedule)
• ??????(test recording procedures)
• ???????(hardware and software requirements)
• ??(constraints)

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2. ????(Software Inspection)

• ?????????????(source representation),???????(anoma
  lies)???(defects)
• ????????,???????????
• ???????????(representation)(????????????)
• ??????????(effective)???

21
?????(Inspection Success)

• ????????????????(inspection)????
• ????,???????(mask)????,???????(several
  executions)
• ??????(reuse domain)????????(programming
  knowledge)??????(reviewers)?????????

22
?????(Inspections and Testing)

• ?????????,?????????
• ???????????????
• ????????????(conformance),?????????????????
• ?????????????,???(performance)????(usability)?

23
????(Program Inspection)

• ?????(document review)?????(formalized approach)
• ??????(detect defect)??????(correct defect)
• ?????????(logical errors)???????(anomalies in the
  code),???????(erroneous condition)(????????(uninit
  ialized variable)),???????(non-compliance with
  standards)

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????????(Inspection Pre-condition)

• ???????(precise specification)
• ?????????????(organisation standards)
• ??????????(syntactically correct code)
• ????????????(error checklist)
• ????????(inspection)???????????????????

25
????
26
????

• ?????(inspection team)??????(system overview)
• ?????????????????
• ?????????????
• ??????????(modification)
• ????(re-inspection)????????

27
????(Inspection Teams)

• ?????????
• ?????????(author)
• ??????(errors)???(omissions)????(inconsistencies)?
  ???(inspector)
• ??????????????(reader)
• ?????????????????(moderator)
• ???????(scribe)????(chief moderator)?????

28
??????(Inspection Checklist)

• ?????????(common error)?????(checklist)?????????(d
  rive the inspection)
• ??????????????(programming language dependent)
• ????(type checking)?????,????????
• ?????(initialization)?????(constant
  naming)?????(loop termination)?????(array bounds)?

29
Inspection Checks
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????(Inspection Rate)

• ?????(overview)?500???(statement)
• ??????,??????125???(statement)
• ?????90?125???(statement)
• ??(inspection)????????(expensive process)
• ??500???(statement)???40??

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3. ???????(Automated Static Analysis)

• ??????(static analyser)?????,?????????(source
  text processing)
• ?????????(parse the program text),????????????,???
  ????VV????
• ????(inspection)?????(effective),??????????

32
??????(Static Analysis Checks)
33
??????

• ??????(control flow analysis)
• ??????(multiple exits)????(entry
  points)???(loop)????????????(unreachable code)?
• ??????(data use analysis)
• ???????(uninitialized)???????????????????(variable
  s written twice without an intervening
  assignment)???????????
• ????(interface analysis)
• ????(routine)?????(procedure)????????

34

• ??????(information flow analysis)
• ??????(output variables)????
• ?????????,??????????????
• ????(path analysis)
• ????????(paths through the program),????????????(s
  tatement),??????(review process)?????

35
LINT ?????
138 more lint_ex.c include ltstdio.hgt printarray
(Anarray) int Anarray printf(d,Anarray)
main () int Anarray5 int i char c
printarray (Anarray, i, c) printarray
(Anarray) 139 cc lint_ex.c 140 lint
lint_ex.c lint_ex.c(10) warning c may be used
before set lint_ex.c(10) warning i may be used
before set printarray variable of args.
lint_ex.c(4) lint_ex.c(10) printarray, arg. 1
used inconsistently lint_ex.c(4)
lint_ex.c(10) printarray, arg. 1 used
inconsistently lint_ex.c(4) lint_ex.c(11) print
f returns value which is always ignored
36
???????

• ?????????(weak typing)???,(?C??),???????????????,?
  ??????????
• ?????????(strong type checking)??(?Java),?????????
  ????,?????????????(less cost-effective)

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4. ??????(Cleanroom Software Development)

• ??(cleanroom)?????????????,????????(defect
  avoidance),??????(defect removal)
• ????????
• ?????(incremental development)
• ????(formal specification)
• ??????(correctness argument)?????(static
  verification)
• ???????(program reliability)?????(statistical
  testing)

38
????(Cleanroom Process)
39
???????

• ????????(state-transition model)?????(formal
  specification)
• ??????(incremental development)
• ???????(structured programming) -???????(limited
  control)??????(abstraction construct)
• ??????(rigorous inspections)?????
• ???????(statistical testing)

40
?????
41
???????(Formal Specification and Inspections)

• ?????????(state based model)???????,??????????????
  (check the program against this model)
• ??????(programming approach)???????????????????(co
  rrespondence)
• ??????(mathematical arguments)(????(proofs))??????
  ?????(confidence)

42
??????(Cleanroom Process Teams)

• ????(specification team)
• ???????????
• ????(development team)
• ?????????
• ?????????????(executed),????????(compiled)

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• ????(certification team)
• ????????,??????????(statistical test)?????
• ???????(reliability growth model)?????????????

44
??????

• ?IBM????(delivered system)???????(faults),????????
  ???
• ?????(independent assessment)?????????????????
• ????????????

45
????

• Ian Sommerville, Software Engineering, 7th ed.,
  Addison-Wesley,2004.