A method for defining an automated test is configured to test a system under test. The system under test includes a plurality of operational states, at least one operational state having executable actions associated therewith operable to execute predetermined operations and/or transition the system under test between operational states. The method includes a) defining an executable model of the system under test including a plurality of model states; and b) defining one or more selectable model actions, each model action representative of one or more executable actions on the system under test and configured such that one or more preconditions are assignable thereto. Each model action is configured to be available to be selected unless any preconditions assigned to the respective model action are not satisfied. The model is configured such that a test program is operable to select a sequence of available model actions to define an automated test.