rover: add exception on unknown Commander command

rover/rover.py

@@ -101,7 +101,7 @@ class Commander(BaseModel):
         return values
 
     def parse_execute(self, commands: str) -> None:
-        for command in commands:
+        for i, command in enumerate(commands):
             save: Vector = deepcopy(self.rover.pos)
             if command == "F":
                 self.rover.forward()
@@ -111,6 +111,8 @@ class Commander(BaseModel):
                 self.rover.turn_left()
             elif command == "R":
                 self.rover.turn_right()
+            else:
+                raise ValueError(f"Unknown command: '{command}' (index {i})")
             if self.rover.pos in self.obstacles:
                 self.rover.pos = save
                 raise ObstacleError

rover/test_rover.py

@@ -1,6 +1,5 @@
 import pytest
 from pydantic import ValidationError
-
 from rover import Commander, Direction, ObstacleError, Rover, Vector
 
 
@@ -222,6 +221,12 @@ def test_commander_complex_command():
     assert com.rover == Rover(dir=Direction.EAST)
 
 
+def test_commander_unknown_command():
+    com = Commander()
+    with pytest.raises(ValueError):
+        com.parse_execute("A")
+
+
 def test_commander_command_with_obstacles():
     com = Commander(obstacles=[Vector(x=1, y=0), Vector(x=1, y=2)])
     with pytest.raises(ObstacleError):