Testing Finite State Machines
- by Pondidum
I have inherited a large and firaly complex state machine at work.
It has 31 possbile states to be in.
It has the following inputs:
Enum: Current State (so 0 - 30)
Enum: source (currently only 2 entries)
Boolean: Request
Boolean: type
Enum: Status (3 states)
Enum: Handling (3 states)
Boolean: Completed
The 31 States are really needed (big business process).
Breaking into seperate state machines doesnt seem feasable - each state is distinct.
I have written tests for one set of inputs (the most common set), with one test per input (all inputs constant, except for the State input):
[Subject("Application Process States")]
public class When_state_is_meeting2Requested : AppProcessBase
{
Establish context = () =>
{
//Setup....
};
Because of = () =>
process.Load(jas, vac);
It Current_node_should_be_meeting2Requested = () => process.CurrentNode.ShouldBeOfType<meetingRequestedNode>();
It Can_move_to_clientDeclined = () => Check(process, process.clientDeclined);
It Can_move_to_meeting1Arranged = () => Check(process, process.meeting1Arranged);
It Can_move_to_meeting2Arranged = () => Check(process, process.meeting2Arranged);
It Can_move_to_Reject = () => Check(process, process.Reject);
It Cannot_move_to_any_other_state = () => AllOthersFalse(process);
}
As no one is entirely sure on what the output should be for each state and set of inputs i have been starting to write tests for it, however on calculation i will need to write 4320 ( 30*2*2*2*3*3*2 ) tests for it.
Does anyone have any suggestions on how i should go about testing this?
