V Model and Testing - KU-SKE17/Software-Process GitHub Wiki

V-Model

Activities or phases in SDLC		V		V&V, including different kinds of testing
Requirements Elicition or...	<->	create acceptance test	->	Acceptance Testing
System Design (Arch)	->	create acceptance test	->	System Testing Integration Testing
Software, Module, or Detail Design
Implantation on (coding)		create Test Plan		Unit Testing

• In Agile
  • developers are supposed to write and run unit tests while writing code
  • use C.I.
• In V-Model
  • last line [Implantation, Test Plan, Unit Testing] might overlap at the same time

Problem when having a developer write tests for his own

• psychological problem
  • The developer doesn't try very hard to make his own code fail
  • Thorough tests -> more work to fix code
• understanding or perspective problem
  • (test from the code, not test from the spec)
  • You write tests based on the code you already wrote, not based on what software should do
  • Your thinking is biased (code for too long)
  • Your tests might be incomplete (fail to test some part of the spec)

2 techniques to measure how thorough our tests

• Code Coverage -> statement coverage, branch coverage, path coverage
• Mutation Testing -> modify some part of the code & run the tests to see if the change is defected
  • Change operators [+, -, *, /, //, %, or, and, not]

What are the current systems and why are they difficult to test

• System with multiple threads and/or events that can arrive in undetermined order
• Different hardware environment can have different number of cores and CPUs, so the number of simultaneously running threads may differ, too.