Levels of Testing

There are 3 levels of testing -

1. Unit Testing- It is the most micro scale of testing; to test particular functions or code modules of an application. It s typically done by the software developer and not by testers.

2. Integration Testing- Testing of combined parts of the application to determine if they function together properly.

There can be two approach for integration testing-

Top-down approach

It starts with main application and successively replaces dummy part with the real modules.

Bottom-up approach

It builds larger module by integrating primitive modules.

Sandwich testing is mainly top-down with bottom-up integration and testing applied to certain most used components..

3. Acceptance Testing- It is final testing based on specifications of the end-user or customer.