System testing of software or hardware is testing conducted on a complete, integrated system to evaluate the system’s compliance with its specified requirements. System testing falls within the scope of black box testing, and as such, should require no knowledge of the inner design of the code or logic.
As a rule, system testing takes, as its input, all of the “integrated” software components that have successfully passed integration testing and also the software system itself integrated with any applicable hardware system(s). The purpose of integration testing is to detect any inconsistencies between the software units that are integrated together (called assemblages) or between any of the assemblages and the hardware. System testing is a more limited type of testing; it seeks to detect defects both within the “inter-assemblages” and also within the system as a whole.
System testing is performed on the entire system in the context of a Functional Requirement Specification(s) (FRS) and/or a System Requirement Specification (SRS). System testing tests not only the design, but also the behavior and even the believed expectations of the customer. It is also intended to test up to and beyond the bounds defined in the software/hardware requirements specification(s).
The following examples are different types of testing that should be considered during System testing:
GUI software testing, Usability testing, Performance testing, Compatibility testing, Error handling testing, Load testing, Volume testing, Stress testing, Security testing, Scalability testing, Sanity testing, Smoke testing, Exploratory testing, Ad hoc testing, Regression testing, Reliability testing, Installation testing, Maintenance testing