System Testing

System Testing is all about

• Test of overall interaction of components
• Find disparities between implementation and specification
• Usually where most resources go to
• Involves –load, performance, reliability and security testing

Goal : to compare the system or program to its original objectives.
Implications :
1) System testing : process of attempting to demonstrate how the program, as a whole, fails to meet its objectives.
2) System testing  : impossible if there is no set of written, measurable objectives for the product.

Common FAQ

 
Who performs system testing and when is it done?

•  Done by the test team
•  Test cases written when high level design spec is ready

Where is it done?

•  Done on a system test machine
•  Usually in a simulated environment  e.g. vmware

Threads in System System

We view system testing in terms of threads of system level behavior.
What is a Thread?
–  A scenario of normal usage
– A system-level test case
– A stimulus-response pair
– Behavior that results from a sequence of system-level inputs.
– An interleaved sequence of port input and output events
– A sequence of transitions in a state machine description of the system



Thread Definitions

• An interleaved sequence of object messages & executions
• A sequence of
  •   Machine instructions
  •   Program statements
  •   MM-paths
  •   Atomic system functions

Thread Levels
Threads have distinct levels : Unit , Integration , System
Unit level
– Thread is understood as an execution time path of instructions or some path on a flow Graph.
– A sequence of DD-paths
– Tests individual functions
Integration level
– Thread  :sequence of MM paths that implement some  SF.
-Sequence of module executions and messages.
– Tests interactions among units
System level
– Thread is a sequence of atomic system functions.
– Tests interactions among ASFs.