// returns the first action that yields a non-null plan, else null
private static IPlanNode <TState, TAction> OrSearch(
TState state,
INonDeterministicSearchProblem <TState, TAction> problem,
IReadOnlyDictionary <TState, IPlanNode <TState, TAction> > explored)
{
if (problem.IsGoal(state))
{
return(EmptyPlan);
}
if (explored.ContainsKey(state))
{
return(explored[state]);
}
foreach (var action in problem.GetActions(state))
{
var orNode = new OrNode <TState, TAction>(action);
var exploredCopy = explored.ToDictionary(e => e.Key, e => e.Value);
exploredCopy[state] = orNode;
var plan = AndSearch(problem.DoAction(state, action), problem, exploredCopy);
if (plan == null)
{
continue;
}
orNode.Child = plan;
return(orNode);
}
return(null);
}
public void GivenOnlyActionLeadsToGoal_FirstSolutionActionShouldGoToGoal()
{
var goalState = new StateMock("goal state");
var goToGoal = new ActionMock("go to goal");
A.CallTo(() => _problem.IsGoal(_initialState)).Returns(false);
A.CallTo(() => _problem.IsGoal(goalState)).Returns(true);
A.CallTo(() => _problem.GetActions(_initialState)).Returns(new [] {goToGoal});
A.CallTo(() => _problem.DoAction(_initialState, goToGoal)).Returns(new[] {goalState});
// act
var solution = CreateSearchAlgorithm(_problem, _initialState).GetSolution();
// assert
Assert.AreEqual(goToGoal, solution.NextAction(_initialState));
}