System testing definitionSystem testing is the testing process in software testing to verify the completeness of system with its original requirement and to find the problems. System testing is start after completing the integration testing. System test is the third phase of testing in STLC. System test is most important phase in STLC because bugs not found in unit and integration testing are founded during system test.
Why system testing require?System testing process is fall under black box testing. Software testing engineer perform system testing on complete integrated system. In system testing techniques, Software tester has to not verify only functionality of the system, But he has to test many different types of testing like load, performance, stress, scalability to verify the complete system behavior. First he tests the system to verify its functionality and then he has to test the system for its performance and more. In system testing, Software test engineer has to test system's all functionality flow wise. He has to check each and every portion of application in depth because this is the final testing of application. In system testing, Software test engineer has to test the integration between software and hardware if any connected to verify its behavior.
Bugs fixing is more time and cost consuming which are founded during the system testing as compared to bugs founded during integration and unit testing.