rover: add obstacle detection to Commander

rover/rover.py

@@ -1,4 +1,6 @@
 import enum
+from copy import deepcopy
+from typing import List
 
 from pydantic import BaseModel
 
@@ -15,6 +17,10 @@ class Direction(enum.Enum):
     WEST = "W"
 
 
+class ObstacleError(RuntimeError):
+    pass
+
+
 DIRECTIONS = [Direction.NORTH, Direction.EAST, Direction.SOUTH, Direction.WEST]
 
 
@@ -60,9 +66,11 @@ class Rover(BaseModel):
 
 class Commander(BaseModel):
     rover: Rover = Rover()
+    obstacles: List[Vector] = []
 
     def parse_execute(self, commands: str):
         for command in commands:
+            save: Vector = deepcopy(self.rover.pos)
             if command == "F":
                 self.rover.forward()
             elif command == "B":
@@ -71,3 +79,6 @@ class Commander(BaseModel):
                 self.rover.turn_left()
             elif command == "R":
                 self.rover.turn_right()
+            if self.rover.pos in self.obstacles:
+                self.rover.pos = save
+                raise ObstacleError

rover/test_rover.py

@@ -1,4 +1,5 @@
-from rover import Commander, Direction, Rover, Vector
+import pytest
+from rover import Commander, Direction, ObstacleError, Rover, Vector
 
 
 def test_rover_constructor():
@@ -217,3 +218,10 @@ def test_commander_complex_command():
     com = Commander()
     com.parse_execute("FRFRFLB")
     assert com.rover == Rover(dir=Direction.EAST)
+
+
+def test_commander_command_with_obstacles():
+    com = Commander(obstacles=[Vector(x=1, y=0), Vector(x=1, y=2)])
+    with pytest.raises(ObstacleError):
+        com.parse_execute("FFRF")
+    assert com.rover == Rover(pos=Vector(x=0, y=2), dir=Direction.EAST)