Software Testing Course

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Software Testing Course

• Shmuel Ur
• ur_at_il.ibm.com
• 8296250

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An interview situation

• How do you know that your program work correctly?
• What part of the total development budget should
  be spent on testing?
• Do you use coverage?
• Can you achieve zero defects?
• Have you ever used a testing tool?

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Administrative details

• 30 optional exercise
• Class slides will be on the class web-site
  (hopefully by Monday)
• Office hours upon request

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Outline

• Foundation of Modern Testing
• Course topics

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Foundation of Modern Testing

• Testing Defined
• Why do we test
• What do we test
• Modern Themes
• Why understanding risks is so important
• Testing as an integrated engineering process
• What is preventive testing

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Why do we test?

• Phase 0 - Testing is debugging (1950s)
• Phase 1 - Show the software works (1970s)
• Phase 2 - Show that the software does not work
  (1975s)
• Phase 3 - Assess quality, evaluation (1980s)
• Phase 4 - Control quality, prevention (1990s)

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What do we test?

• Unit testing
• Component testing
• Integration testing
• System testing
• Regression testing
• Acceptance Testing
• Usability Testing

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More thing we test

• Field Testing
• Stress or capacity testing
• Platform testing
• Performance Testing
• Viral protection testing

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Why understanding risks is so important

• Bug importance f (frequency, correction_cost,
  instaltion_cost, consequences)
• Bug consequences scale mild, moderate, annoying,
  disturbing, serious, very serious, extreme,
  intolerable, catastrophic, infectious.
• Quantifying risk leads to cost-effective test
  sets

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What is preventive testing?

• Using tests to influence and control software
  design and development
• Implicit concurrent engineering of testware and
  software
• Preventive testing is built on the observation
  that one effective way to specifying something is
  to describe (in detail) how you would accept
  (test) the something if someone gave it to you.
• Bill Hetzel

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Side-effects are important

• The side-effect of early test preparation can be
  more important than later results.
• Side-effects
• Better communication
• Clearer and better understood requirements
• better design definition and understanding
• more reliable implementations
• Higher quality software!

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Key elements of preventive testing

• Tests are used as requirements models
• Testware design leads software design
• Defects are detected earlier or prevented
  altogether
• Defects are systematically analyzed
• Tester and developers work together

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Why is testing so difficult?

• Testing is a challenge because
• Complexity of software products
• Nature of software behavior and problems
• Large amounts of information required
• Plus Frustration due to
• Attitude, Communication, Schedule, Resources,
  Documentation, Requirements,
• Changes, .....

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Foundation of Modern Testing Summary

• Testing is planning, designing, building,
  executing maintaining testware
• We test for many reasons
• Good testing drives good quality
• testing produces a product
• Software and testware are strongly co-dependent

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Topics to be covered

• Coverage
• Regression
• Bug Classifications
• Requirement Check List
• Test Specifications
• Code Inspection

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Topics to be covered II

• Software Reliability
• Risks and Bug Taxonomy
• Domain Specific Test Generators
• OO Testing
• Ma
• Matrix and Complexity

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Topics to be covered III

• Test Tools
• Formal Verification
• Automatic Test Generators
• Random Test Generators
• Exploratory Testing