Example: One Feature “Bank transaction” consist of 5 modules such as
- Login (Developed by Coder 1)
- Current Balance (Developed by Coder 2)
- Deposit (Developing by Coder 3)
- Withdraw (Developing by Coder 4)
- Transfer (Developing by Coder 5)
Feature 1 and 2 is ready but the other features are not done yet. In this case we have 2 options
Big – Bang testing and Incremental Testing
Big – Bang Testing: Have to wait for all the modules to be developed. So this is time consuming and difficult to trace root case of bugs.
Incremental Testing: Modules are tested as and when they are available. According to the example, testing of Current Balance module can be begin by creating demo module of Transfer called Stub. It can be Top to Down or Down to Top.
STUB : get value and return response
Transfer Module : It will be progress independently such as validations and other staffs

Images comes from https://www.youtube.com/watch?v=goaZTAzsLMk