Computer-implemented methods and apparatuses for application testing are provided. Such apparatuses may include a data repository that stores a copy of at least some of a set of stored reference data. Such apparatuses may also include a test data generation component that generates a set of input data for testing the application. The test data generation component may process a set of received input data and the set of stored reference data according to a data processing operation. The set of received input data and set of stored reference data may each comprise one or more attributes, each with at least one value. The test data generation component may generate the set of input data by selecting at least one value from the copy of the set of stored reference data, and outputting the selected at least one value in the generated set of input data for testing the application.