TestingGeek

In bottom up integration testing, module at the lowest level are developed first and other modules which go towards the 'main' program are integrated and tested one at a time. Bottom up integration also uses test drivers to drive and pass appropriate data to the lower level modules. As and when code for other module gets ready, these drivers are replaced with the actual module. In this approach, lower level modules are tested extensively thus make sure that highest used module is tested properly.

• Behavior of the interaction points are crystal clear, as components are added in the controlled manner and tested repetitively.
• Appropriate for applications where bottom up design methodology is used.

• Writing and maintaining test drivers or harness is difficult than writing stubs.
• This approach is not suitable for the software development using top down approach.