Integration testing is a software testing methodology used to test individual software components or units of code to verify interaction between various software components and detect interface defects. Components are tested as a single group or organized in an iterative manner. After the integration testing has been performed on the components, they are readily available for system testing. After completion of the development each developer code put in current project folder,test this new code with old through the batch to check the new functionality and old functionality based on the subject areas. Entire process is called integration testing.