e.message == "<state> should be in state C or later."
    }

    def "maybeTransition() runs action for transition when in from state"() {
        def action = Mock(Runnable)
        def controller = controller(TestState.A)

        when:
        asWorker {
            controller.maybeTransition(TestState.A, TestState.B, action)
        }

        then:
        1 * action.run()

        return state.notInStateIgnoreOtherThreads(State.Finished, modelController::getConfiguredModel);
    }

    @Override
    public void prepareToScheduleTasks() {
        state.maybeTransition(State.Configure, State.TaskSchedule, () -> {
            hasTasks = true;
            modelController.prepareToScheduleTasks();
        });
    }

    @Override
    public BuildWorkPlan newWorkGraph() {

     * Blocks until other operations are complete.
     */
    public void maybeTransition(T fromState, T toState, Runnable action) {
        synchronizer.withLock(() -> {
            if (state.inStateAndNotTransitioning(toState)) {
                return;
            }