The following types of testing are involved in functional testing:
- Mainline functions:  Testing the main functions of an application
 
- Basic Usability: It involves basic usability testing of the system. It checks whether a user can freely navigate through the screens without any difficulties.
 
- Accessibility:  Checks the accessibility of the system for the user
 
- Error Conditions: Usage of testing techniques to check for error conditions.  It checks whether suitable error messages are displayed.