Method and apparatus for performing Pattern-Controlled tests on an automatic test equipment (ATE). The ATE includes a diagnostic instrument and a control device. An application programming interface (API) is installed in the control device and operates to interact with a test program and thereby automatically controls the diagnostic instrument to perform a test. The test program is coded in a high-level programming language and defines a plurality of operation events for the test based on user input. The API identifies the operational events and determines respective operational types associated therewith. Events of an operational type are assigned to a respective pattern label. The pattern labels are then aggregated into a pattern burst which is downloaded to the diagnostic instrument.