Integration testing tests integration or interfaces between components, interactions to different parts of the system such as an operating system, file system and hardware or interfaces between systems. Integration testing is a key aspect of software testing.
- After integrating two or more different components together we do the integration testing.
- Integration testing is done by a specific integration tester or test team.
- Integration testing follows three approach known as ‘Top Down’ approach and ‘Bottom Up’ approach and Big Bang Approach.
Top-down Integration Testing
Testing takes place from top to bottom, following the control flow or architectural structure (e.g. starting from the GUI or main menu). Components or systems are substituted by stubs.
Bottom up Integration Testing
Testing takes place from the bottom of the control flow upwards. Components or systems are substituted by drivers.
Big Bang Integration Testing
In Big Bang integration testing all components or modules are integrated simultaneously, after which everything is tested as a whole.