Performance Testing

Performance Testing
The goal of performance testing is not to find bugs, but to eliminate bottlenecks and establish a baseline for future regression testing. To conduct performance testing is to engage in a carefully controlled process of measurement and analysis.

Load Testing
Load testing operates at a predefined load level, usually the highest load that the system can accept while still functioning properly. Note that load testing does not aim to break the system by overwhelming it, but instead tries to keep the system constantly humming like a well-oiled machine.

Stress Testing
Stress testing tries to break the system under test by overwhelming its resources or by taking resources away from it (in which case it is sometimes called negative testing). The main purpose behind this madness is to make sure that the system fails and recovers gracefully -- this quality is known as recoverability.

Where performance testing demands a controlled environment and repeatable measurements, stress testing joyfully induces chaos and unpredictability. Stress testing does not break the system purely for the pleasure of breaking it, but instead it allows testers to observe how the system reacts to failure.