Editing Software performance testing (section)

== Prerequisites ==
A stable build of the system which must resemble the production environment as closely as is possible.

To ensure consistent results, the performance testing environment should be isolated from other environments, such as [[user acceptance testing]] (UAT) or development. As a best practice it is always advisable to have a separate performance testing environment resembling the production environment as much as possible.

=== Test conditions ===
In performance testing, it is often crucial for the test conditions to be similar to the expected actual use. However, in practice this is hard to arrange and not wholly possible, since production systems are subjected to unpredictable workloads. Test workloads may mimic occurrences in the production environment as far as possible, but only in the simplest systems can one exactly replicate this workload variability.

Loosely-coupled architectural implementations (e.g.: [[Service-oriented architecture|SOA]]) have created additional complexities with performance testing. To truly replicate production-like states, enterprise services or assets that share a common [[infrastructure]] or platform require coordinated performance testing, with all consumers creating production-like transaction volumes and load on shared infrastructures or platforms. Because this activity is so complex and costly in money and time, some organizations now use tools to monitor and simulate production-like conditions (also referred as "noise") in their performance testing environments ([[Performance test (assessment)|PTE]]) to understand capacity and resource requirements and verify / validate quality attributes.

=== Timing ===
It is critical to the cost performance of a new system that performance test efforts begin at the inception of the development project and extend through to deployment. The later a performance defect is detected, the higher the cost of remediation. This is true in the case of functional testing, but even more so with performance testing, due to the end-to-end nature of its scope. It is crucial for a performance test team to be involved as early as possible, because it is time-consuming to acquire and prepare the testing environment and other key performance requisites.