Abstract: Methods, systems, and computer-readable storage media for selecting columns for generating test data for an application that is to be tested. Implementations include actions of receiving user input indicating an entity of the application, receiving a data structure of the entity, the data structure providing a set of elements of the entity, the set of elements including one or more elements, each element being associated with a value type, displaying the set of elements, each element being associated with a rule defining how values of the respective element are to be provided, and providing test data for elements of the set of elements based on respective rules, the test data including values that are semantically correct for a respective type.