Software Testing Levels

Philippe CHARMANcharman@fr.ibm.com

http://users.polytech.unice.fr/~charman/

Last update: 25-04-2014

Main Testing Levels

• Component Testing• Integration Testing• System Testing• Acceptance Testing

Testing LevelsWith A Basic Architecture

Integration Testing

Low Level Code

High Level Code

Component A

Low Level Code

High Level Code

Component B

Acceptance Testing

System Testing

Component Testing

CustomerDB

App Server

Component Testing

• Testing individual software components

• Benefits:– Tests unit are easy and simple to write– Allow to detect bugs sooner in the development cycle when

written at a first stage– Can be run as non-regression tests later on– Ease the debug

• Limitation:– Cannot test globally the application

• Should be written by developers or testers having access to the source code

Integration Testing

• Testing level in which individual software modules are combined and tested as a group

• 3 approaches:

– Big Bang

– Top-down

– Bottom-up

System Testing

• Process of testing an integrated system to verify it meets specified requirements

• Purpose : find as many bugs as possible

• Testing both functional and non-functional requirements of the system

• Specification-based and structure-based techniques

• Executed by the development organization

Acceptance Testing

• Performed by the customer mainly and the consultant also

• They may detect:

– My needs are not really satisfied

– Performance issues

– Usability issues

– Customer Data issues

• Alpha testing ~= internal acceptance testing

– Performed at the developers site

• Beta testing ~= internal acceptance testing

• Performed at an external site

Testing LevelsWho Tests What

ComponentTesting

IntegrationTesting

SystemTesting

Low Level Code

High Level Code

Component A

Low Level Code

High Level Code

Component B

CustomerDB

Acceptance Testing

Dev

elop

er

Tes

ter

Con

sulta

nt

Cus

tom

er

App Server