In Big Bang integration testing all components or modules are integrated simultaneously, after which everything is tested as a whole.

• In this approach individual modules are not integrated until and unless all the modules are ready.
• In Big Bang integration testing all the modules are integrated without performing any integration testing and then it’s executed to know whether all the integrated modules are working fine or not.
• This approach is generally executed by those developers who follows the ‘Run it and see’ approach.
• Because of integrating everything at one time if any failures occurs then it become very difficult for the programmers to know the root cause of that failure.
• In case any bug arises then the developers has to detach the integrated modules in order to find the actual cause of the bug.

Below is the image of the big bang integration testing:

Suppose a system consists of four modules as displayed in the diagram above. In big bang integration all the four modules ‘Module A, Module B, Module C and Module D’ are integrated simultaneously and then the testing is performed. Hence in this approach no individual integration testing is performed because of which the chances of critical failures increases.

Advantage of Big Bang Integration:

• Big Bang testing has the advantage that everything is finished before integration testing starts.

Disadvantages of Big Bang Integration:

• The major disadvantage is that in general it is very time consuming
• It is very difficult to trace the cause of failures because of this late integration.
• The chances of having critical failures are more because of integrating all the components together at same time.
• If any bug is found then it is very difficult to detach all the modules in order to find out the root cause of it.
• There is high probability of occurrence of the critical bugs in the production environment