1. A method for testing an event processing system, comprising: applying a sliding window on a stream of input events that are sent to an event processing system, wherein said event processing system processes the stream of input events in a batch mode with one or more sliding cycles, and wherein said sliding window includes one or more input events in a sliding cycle that correspond to a plurality of expected output events; receiving a plurality of actual output events at an end of said sliding cycle in the batch mode from the event processing system; and using said one or more expected output events to verify said one or more actual output events.