1. A method of testing elements of a pipeline software system, comprising: as the pipeline software system executes, receiving information about a state of the pipeline software system; saving, according to a data model, the information as representative of conditions existing within the pipeline software system; and replaying execution of the pipeline software system using the data model and without requiring initialization and re-execution of the pipeline to perform a development action with respect to an element; wherein at least one of the receiving, saving and replaying steps is carried out in software executing in a hardware element.