This week I've been playing with altwalker , a model-based testing tool. To get the hang of it, I attempted to build a very simple model of a workflow that is supported by the service my team owns. Hacking away at the example code, and looking frequently at the docs, I was able to get up and running in a few hours, creating: a basic model: nodes for system states, edges for operations simple assertions: mainly consistency checks on the states client: HTTP client to implement the operations against the service's API I configured this so that altwalker will perform a random walk of the model, starting state data is randomised, and the client will choose randomly whenever offered an option. Why so much randomness? Because it means that, over successive runs, more of the infinite space of possible workflow executions will be covered. Once I had that basically working I wrote a shell script that would run this loop a number of times: call altwalker ...