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c++unit-testingboostboost-statechart

Unit testing with boost::statechart

We are using the boost statechart library and have troubles writing unit tests for the code.

In our normal execution the state machine starts in ClosedState:

struct BoostStateMachine : sc::state_machine<BoostStateMachine, ClosedState >

We would like to test a specific state transition without having to traverse the state machine till that state, for example we would like to start the test in AnotherState. The problem is that sc::state_machine is templated on its initial state. Feeding the state machine with all the events that lead to the tested states, usually requires a lot of work and complicates the tests.

A primitive solution is to write special debug-only event and add it to ClosedState. This event will trigger an immediate transition to AnotherState.

Do you know any other way to accomplish the task?

Solution

  • I'll admit it's not great, but

    #ifdef DEBUG
typedef AnotherState StartingState;
#else
typedef ClosedState StartingState;
#endif
struct BoostStateMachine : sc::state_machine<BoostStateMachine, StartingState > {...

    EDIT addressing comment

    #ifndef INITIAL_STATE
#define INITIAL_STATE ClosedState
#endif
struct BoostStateMachine : sc::state_machine<BoostStateMachine, INITIAL_STATE > {...

    of course that means you need to recompile to do each test =[

    We could try the following:

    typedef<class InitialState>
struct StateMachine : sc::state_machine< typename /*?*/ StateMachine<InitialState>, InitialState > {...}

typedef StateMachine<ClosedState> BoostStateMachine; //default case

#ifdef DO_TESTS
    ...
    StateMachine<AnotherState> astate1;
    ...
    StateMachine<AnotherState2> astate2;
    ...
    StateMachine<AnotherState3> astate3;
    ...
#endif

    This of course does not help when it's a substate that needs to start in a different state. But the same thing could apply:

    typedef <typename InitialChild>
struct ClosedState : sc::simple_state< ClosedState<InitialChild>, BoostStateMachine, InitialChild > {...};

    or something like it. I have done templated states before (so that I could have common sub-state sequences) and it is a royal PITA to debug (more so that the rest of statechart).