Testing the data flow or interface between two features is known as integration testing.

 In Integration Testing, we must remember the following points,

• Understand the application thoroughly i.e., understand how each and every feature works. Also understand how each and every feature are related or linked to each other.
• Identify all possible scenarios
• Prioritize all the scenarios for execution
• Test all the scenarios
• If you find defects, communicate defect report to developers
• Do positive and negative integration testing.
• Positive – if there is total balance of 10,000 – send 1000rs and see if amount transfer works fine – if it does, then test is pass. Negative – if there is total balance of 10,000– send 15000rs and see if amount transfer happens – if it doesn’t happen, test is pass – if it happens, then there is a bug in the program and send it to development team for repairing defects.

There are two types of integration testing,

 Integration Testing

• Incremental integration testing is a method of testing often used in Agile projects where a module is tested, then integrated with another module. That integration is tested, and then another module or component is added.
•                Top-Down Incremental Integration Testing:  The top down integration testing method is an incremental approach that involves joining two or more logically related modules. The process involves using dummy programs called Stubs and Drivers to stimulate the behavior of unintegrated lower-level modules.
• Bottom-Up Incremental Integration Testing :  Bottom-up integration testing is a technique that starts with testing the lowest-level or most independent modules of a system and gradually integrates them with higher-level or more dependent modules.
• Non-incremental integration testing is a method that involves integrating and testing all the units or modules at once, after they have been individually tested and verified. This way, you can save time and resources, avoid redundant testing, and test the system as a whole.