Which of the following is usually the test basis for integration testing?

Integration testing primarily focuses on assessing the interactions between various components or systems that have been integrated. The test basis for integration testing is typically derived from a variety of specifications related to how these components interact.

The most relevant basis for integration testing is the technical specification. This is because the technical specifications provide detailed information about the architecture, interfaces, and data flow between different modules or components. These specifications cover aspects such as how components communicate with one another, the protocols they use, and the expected data structures. Such details are crucial for understanding how to effectively prepare the integration test cases and scenarios, ensuring that all interactions are validated against what is technically defined.

In contrast, while the program, functional, and requirement specifications are essential for other testing levels, they do not provide the same level of detailed technical insight necessary for integration testing. The program specification may cover individual module logic, the functional specification might detail what the system is supposed to do at the feature level, and the requirement specification outlines user needs and business goals. However, it is the technical specification that gives the necessary context for how components work together, making it the most appropriate test basis for integration testing.