Quality is delighting customers
Functional Testing : To check the whether the implemented functionality is working fine or not.
Regression Testing : After the bug fixes is done, to check if because of that fixes is there any new bugs introduced.
Integration Testing : To check the interaction between the two modules are working fine or not.
System Integration Testing : To check whether the application is working fine or now while integrate with other system.
System testing : It is nothing but the End-to-End testing of the application. It contains both functional and non functional testing.