Update the TicTacToe environment

pettingzoo/classic/tictactoe/board.py

@@ -1,10 +1,3 @@
-class BadTicTacToeMoveException(Exception):
-    """Exception raised when a bad move is made on TicTacToe board."""
-
-    def __init__(self, message="Bad TicTacToe move"):
-        super().__init__(message)
-
-
 TTT_PLAYER1_WIN = 0
 TTT_PLAYER2_WIN = 1
 TTT_TIE = -1
@@ -80,15 +73,11 @@ def play_turn(self, agent, pos):
         * The spot must be be empty.
         * The spot must be in the board (integer: 0 <= spot <= 8)
 
-        If any of those are not true, a BadTicTacToeMoveException
-        will be raised.
+        If any of those are not true, an assertion will fail.
         """
-        if pos < 0 or pos > 8:
-            raise BadTicTacToeMoveException("Invalid move location")
-        if agent != 0 and agent != 1:
-            raise BadTicTacToeMoveException("Invalid agent")
-        if self.squares[pos] != 0:
-            raise BadTicTacToeMoveException("Location is not empty")
+        assert pos >= 0 and pos <= 8, "Invalid move location"
+        assert agent in [0, 1], "Invalid agent"
+        assert self.squares[pos] == 0, "Location is not empty"
 
         # agent is [0, 1]. board values are stored as [1, 2].
         self.squares[pos] = agent + 1

pettingzoo/classic/tictactoe/test_board.py

@@ -11,7 +11,6 @@
     TTT_PLAYER1_WIN,
     TTT_PLAYER2_WIN,
     TTT_TIE,
-    BadTicTacToeMoveException,
     Board,
 )
 
@@ -113,16 +112,16 @@ def test_tictactoe_bad_move() -> None:
     board = Board()
     # 1) move out of bounds should be rejected
     for outside_space in [-1, 9]:
-        with pytest.raises(BadTicTacToeMoveException):
+        with pytest.raises(AssertionError):
             board.play_turn(0, outside_space)
 
     # 2) move by unknown agent should be rejected
     for unknown_agent in [-1, 2]:
-        with pytest.raises(BadTicTacToeMoveException):
+        with pytest.raises(AssertionError):
             board.play_turn(unknown_agent, 0)
 
     # 3) move in occupied space by either agent should be rejected
     board.play_turn(0, 4)  # this is fine
     for agent in [0, 1]:
-        with pytest.raises(BadTicTacToeMoveException):
+        with pytest.raises(AssertionError):
             board.play_turn(agent, 4)  # repeating move is not valid