In a top-down development strategy, which level of testing is mainly affected?

In a top-down development strategy, integration testing is primarily affected because this approach begins with the higher-level components or modules of a system and progressively integrates lower-level components. Initially, when higher-level components are developed, testing focuses on verifying their functionality and interactions with other components that may be mocked or stubbed, to mimic the eventual behavior of lower-level components.

This means that integration testing, which is concerned with the interaction between integrated components, plays a crucial role in this strategy as it ensures that the higher-level components work seamlessly with those lower-level components as they are later integrated. As the lower levels are developed, more integration tests occur to verify that the interactions remain correct.

The other levels of testing, such as component testing and system testing, are not primarily impacted in this strategy as they focus on the testing of individual components and the full system, respectively, rather than the integration of higher-level modules. User acceptance testing occurs even later in the development process, focusing on validation by end-users against requirements, further distancing it from the impacts of a top-down approach during initial integration phases.