What are different approaches to do Integration Testing?

Integration testing is black box testing. Integration testing focuses on the interfaces between units, to ensure that units work together to complete a specify task. The purpose of integration testing is to confirm that different components of the application interact with each other. Integration testing is considered complete, when actual results and expected results are same. There are mainly three approaches to do integration testing.

- Top-down Approach: Tests the components by integrating from top to bottom.
- Bottom-up approach: It takes place from the bottom of the control flow to the higher level components
- Big bang approach: In this are different module are joined together to form a complete system and then testing is performed on it.