This is a test case generator for software (or anything, really) with a clear set of states, and transitions connecting all the states.
The python code has the logic for traversing the states and transitions in the form of a Multi-DiGraph. This allows us to find the smallest path that covers the transitions, and as a result also covers the states in that graph.
This is basically a solution to the chinese postman path problem. (Not to be confused with the Travelling Salesman problem)