Unit Tests are conducted by developers and test the unit of code( aka module, component) he or she developed. It is a testing method by which individual units of source code are tested to determine if they are ready to use. It helps to reduce the cost of bug fixes since the bugs are identified during the early phases of development life cycle.
Integration testing is executed by testers and tests integration between software modules. It is a software testing technique where individual units of a program are combined and tested as a group. Test stubs and test drivers are used to assist in Integration Testing. Integration test is performed in two way, they are bottom-up method and the top-down method.
Below is a detailed comparison between the two-
The idea behind Unit Testing is to test each part of the program and show that the individual parts are correct.
The idea behind Integration Testing is to combine modules in the application and test as a group to see that they are working fine