Big Bang Integration Testing
Big bang integration testing combines every module of a system at once and tests them together as a whole, rather than integrating and testing incrementally. It's fast to set up but makes failures hard to isolate — when something breaks, there's no way to tell which of the many newly-combined modules caused it.
The appeal of big bang integration is simplicity: no need to plan an integration order, build stubs for not-yet-integrated modules, or stage the work — everything just gets wired together and tested in one pass, once all the pieces exist.
The cost shows up the moment something fails. With dozens of modules integrated simultaneously, root cause analysis becomes a much bigger search space than it would be with incremental integration, where each step only introduces one new module's worth of risk at a time. It's generally reserved for smaller systems or situations where incremental integration isn't practical.
