7.4. Load Testing

Once an application is working correctly, both in terms of its individual components and as a whole, it’s helpful to know how that application performs as a whole. Load testing involves simulating activity for a group of users to determine how well the application performs under the load.

This information can be useful in two major ways. First, if you have specific expectations for the load an application will need to handle when it’s deployed to production, load testing can provide a rough estimate of how much server hardware will be required. Second, while an application is being developed or maintained, load testing can expose changes that may significantly impact performance, especially if automated load tests are included in a continuous integration environment—that is, a repeated series of quality control processes.