Teste e Qualidade de Software

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Teste e Qualidade de Software

• 10 de Dezembro de 2004

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Todos os programas têm erros ...
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Leis de Murphy dos Computadores

• Todo o programa tem erros
• Todo o programa tem sempre mais um erro
• O número de erros num programa é dado
  precisamente pela fórmula n gt aem que a é um
  inteiro qualquer
• Só há 2 maneiras de fazer um programa sem erros,
  mas só a 3ª é que funciona

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Estado actual da qualidade do software

• Microsoft Windows XP End-User License Agreement
• 11. LIMITED WARRANTY FOR PRODUCT ACQUIRED IN
  THE US AND CANADA. Microsoft warrants that the
  Product will perform substantially in accordance
  with the accompanying materials for a period of
  ninety days from the date of receipt.() If an
  implied warranty or condition is created by your
  state/jurisdiction and federal or
  state/provincial law prohibits disclaimer of it,
  you also have an implied warranty or condition,
  BUT ONLY AS TO DEFECTS DISCOVERED DURING THE
  PERIOD OF THIS LIMITED WARRANTY (NINETY DAYS).
  ()Some states/jurisdictions do not allow
  limitations on how long an implied warranty or
  condition lasts, so the above limitation may not
  apply to you.()YOUR EXCLUSIVE REMEDY.
  Microsoft's and its suppliers' entire liability
  and your exclusive remedy shall be, at
  Microsoft's option from time to time exercised
  subject to applicable law, (a) return of the
  price paid (if any) for the Product, or (b)
  repair or replacement of the Product, that does
  not meet this Limited Warranty and that is
  returned to Microsoft with a copy of your
  receipt. (..)This Limited Warranty is void if
  failure of the Product has resulted from
  accident, abuse, misapplication, abnormal use or
  a virus.

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É importante detectar e corrigir os erros o mais
cedo possível ...
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Custos de não-qualidade

• (source "Software Project Survival Guide", Steve
  McConnell)

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Custos de não-qualidade

• (source "Software Testing", Ron Patton)

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Quando e como ...
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Quando e como

• (source "Software Project Survival Guide", Steve
  McConnell)

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Melhor do que detectar e corrigir erros, é
prevenir erros ...
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Prevenir erros

• Detectar "The goal of a software tester is to
  find bugs, find them as early as possible, and
  make sure that they get fixed" (Ron Patton)
• Prevenir "A software quality assurance person's
  main responsibility is to create and enforce
  standards and methods to improve the development
  process and to prevent bugs from ever occurring"
• Actuar a nível do processo!

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A qualidade atinge-se com o envolvimento de todos
...
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Quem está envolvido
Software Development Organization
goals
Software Development Process
Demand, Needs
Costumer or Market
Software Product
project manager
software developer
software tester
software quality (assurance) engineer
Customer external or internal
resources
Product product or service
Test test and review
Development development and maintenance
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Mais informação

• Página da disciplina no SiFEUP
• Página mantida pelo docente na edição 2003/04
  (acessível a partir do SiFEUP)