Which testing method focuses on the program's performance with a large volume of data?

The focus of the load test is specifically on evaluating how well a program performs under stress, particularly with a substantial volume of data or simultaneous users. This type of testing aims to determine the system's behavior and responsiveness when subjected to high demands, which can include the number of transactions, data throughput, and user activity. By simulating the expected usage load and measuring performance metrics such as response times, error rates, and server resource utilization, load testing helps to identify potential bottlenecks or areas where the system may fail when faced with heavy use.

In contrast, unit tests are designed to check individual components or functions of the software to ensure they perform as expected in isolation. Security tests focus on identifying vulnerabilities and ensuring the software is resistant to attacks. Integration tests validate the interactions between different modules or services within the application, ensuring they work together correctly. While these tests are crucial for overall software quality, they do not specifically address performance under heavy data conditions like load tests do.