What type of testing can developers conduct on OutSystems applications?

The correct answer encompasses a comprehensive approach to ensuring the quality and reliability of OutSystems applications by including unit testing, integration testing, and user acceptance testing.

Unit testing focuses on verifying the smallest parts of the application, such as individual functions or methods, to ensure that they perform as expected. This allows developers to catch bugs early in the development process. Integration testing follows by assessing how various modules or services within the application interact with one another, which is crucial for identifying issues that arise when different components are combined.

User acceptance testing (UAT) is the final phase where actual users test the application to determine if it meets their needs and expectations. This kind of testing is essential for obtaining feedback before the application goes live. By completing these three types of testing, developers ensure a robust application that meets functional requirements and is fit for user interaction.

The other options focus on specific aspects of testing or are limited in scope. Load testing and performance testing, for example, are significant but do not capture the full breadth of testing developers can perform. Similarly, functionality and deployment testing focus only on certain areas of the application, while compliance testing pertains specifically to adherence to regulatory standards, which limits its applicability in overall application quality assurance.