private static string PerformSimulation(
LawnMowerState initialState,
LawnSize lawnSize,
LawnMowerCommand[] commands)
{
var simulator = new LawnMowerMovementSimulator();
try
{
var lawnMowerSteps =
simulator.SimulateMovement(
initialState,
lawnSize,
commands);
var finalState = lawnMowerSteps
.Last();
return($"{finalState.Position.X} {finalState.Position.Y} {finalState.Direction.Sign}");
}
catch (CannotMoveOutsideLawnBoundariesException)
{
return("Mower tried to cut rare plants");
}
}
public void GetStateAfterMoveForward_ShouldReturnCorrectNewState()
{
var originalState = new LawnMowerState(new Position(5, 10), Direction.East);
var expectedNewState = new LawnMowerState(new Position(6, 10), Direction.East);
var newState = originalState.GetStateAfterMoveForward();
newState
.Should()
.Be(expectedNewState);
}
public void GetStateAfterLeftTurn_ShouldReturnCorrectNewState()
{
var originalState = new LawnMowerState(new Position(5, 10), Direction.East);
var expectedNewState = new LawnMowerState(new Position(5, 10), Direction.North);
var newState = originalState.GetStateAfterLeftTurn();
newState
.Should()
.Be(expectedNewState);
}
public void ParseLawnMowerState_ShouldReturnCorrectStateWhenInputIsValid(
string input,
int expectedX,
int expectedY,
char expectedDirectionSign)
{
var inputParser = new InputParser();
var parsedState = inputParser.ParseLawnMowerState(input);
var expectedState = new LawnMowerState(
new Position(expectedX, expectedY),
Direction.GetBySign(expectedDirectionSign));
parsedState
.Should()
.Be(expectedState);
}
private LawnMowerState PerformCommand(
LawnMowerState state,
LawnMowerCommand command)
{
switch (command)
{
case LawnMowerCommand.TurnRight:
return(state.GetStateAfterRightTurn());
case LawnMowerCommand.TurnLeft:
return(state.GetStateAfterLeftTurn());
case LawnMowerCommand.MoveForward:
return(state.GetStateAfterMoveForward());
default:
throw new UnknownLawnMowerCommandException();
}
}
private IEnumerable <LawnMowerState> SimulateMovementImpl(
LawnMowerState initialState,
LawnSize lawnSize,
IEnumerable <LawnMowerCommand> commands)
{
var currentState = initialState;
foreach (var command in commands)
{
currentState = PerformCommand(currentState, command);
if (!lawnSize.IsPositionWithinLawn(currentState.Position))
{
throw new CannotMoveOutsideLawnBoundariesException();
}
yield return(currentState);
}
}
public IEnumerable <LawnMowerState> SimulateMovement(
LawnMowerState initialState,
LawnSize lawnSize,
IEnumerable <LawnMowerCommand> commands)
{
if (initialState == null)
{
throw new ArgumentNullException(nameof(initialState));
}
if (lawnSize == null)
{
throw new ArgumentNullException(nameof(lawnSize));
}
if (commands == null)
{
throw new ArgumentNullException(nameof(commands));
}
// actual implementation is in separate method to force execution of arguments checks before iterating the result
return(SimulateMovementImpl(initialState, lawnSize, commands));
}
