end-to-end (E2E) testing, is testing conducted on a complete software system.
System testing describes testing as at the system level to contrast to testing at the integration or unit level.
System testing often serves the purpose of evaluating the system's compliance with its specified requirements [citation needed] – often from a functional requirement specification (FRS), a system requirement specification (SRS), another type of specification or multiple.
[citation needed] [1] System testing can verify the design, the behavior and even the believed expectations of the customer.
It is also intended to test up to and beyond the bounds of specified software and hardware requirements.