Difference between Functional and Non-Functional Testing

Functional Testing: 

1. Testing the application against business requirements. Functional testing is done using the functional specifications provided by the client or by using the design specifications like use cases provided by the design team.
2. Functional testing is concerned only with the functional requirements of a system or subsystem and covers how well (if at all) the system executes its functions. These include any user commands, data manipulation, searches and business processes, user screens, and integrations.
3. Functional testing is done using the functional specifications provided by the client or by using the design specifications like use cases provided by the design team.