Integration Testing

Will developer do testing?
Yes,developer done testing called unit test only.
Unit Testing
Unit Testing is a software testing method in which individual units or components of a software application (such as functions, methods, or classes) are tested in isolation to verify that they work correctly as expected.It helps find and fix defects at the very beginning of the development cycle, reducing the cost and effort of debugging later.
Aftet test case writing testers what can do?
After test case writing testers will do preparation for test environment or test bed preparation. Test bed preparation is nothing but Create a environment for OS, browsers, hardware, network, db service etc..
Integration Testing
Integration testing is done by testers.It is nothing but combining more than one unit and testing. It has 2 areas top down approach and bottom up approach.
Integration testing is a software-testing approach in which various application components or modules are joined and tested to evaluate how well they work together.
Real-World Example
E-Commerce Website: Integration testing ensures different modules of an online shopping platform—product catalog, shopping cart, payment gateway, and user accounts work together correctly.
Top Down Approach
Top-Down Testing is an incremental integration testing approach in which testing begins with high-level modules and gradually moves down to lower-level modules. It verifies system functionality by integrating components from top to bottom through the control flow.
Example:
First we test the sign up - after sign up we test the sign in then we test the sign out.After sign out the sign in function work well or not to be test .If password will be forgot that function work well or not to be test.This example will be test in reverse is called Bottom up approach.
Bottom Up Approach
In Bottom-Up Integration Testing, lower-level modules are tested first, followed by gradual integration of higher-level modules.
Stubs and Drivers
Stubs is a dummy temporary software (like for sign up)will be given to tester.It is used in both the approach but mainly focuses on top down approach. It is known as called program.
Driver is also a dummy temporary software which drives the other module.It is used in both the apporach but mainly focuses on bottom up approach.It is known as calling program.
References
https://www.geeksforgeeks.org/software-testing/software-engineering-integration-testing/
https://www.geeksforgeeks.org/software-engineering/steps-in-top-down-integration-testing/