1. A system comprising: one or more processors; one or more computer-readable media having computer-readable instructions thereon which, when executed by said one or more processors, cause said one or more processors to: model software using a software model that describes behavior associated with the software, the software model comprising a state graph having multiple nodes individual ones of which represent a state, and links between the nodes that represent actions; and operate on the software model using a random destination algorithm and at least one other different algorithm to produce a sequence of test actions, the random destination algorithm being configured to randomly select a destination node in the model and move to that destination node to produce the sequence of test actions, the selection of the destination node being performed independent of any previously-traversed nodes, and independent of any nearest neighbor nodes.