create better future planning into BestBattleSnake

tests/test_BestBattleSnake.py

@@ -829,5 +829,197 @@ class TestBestBattleSnake(unittest.TestCase):
     move = make_board(game_state).snake_neat_make_a_move()
     self.assertEqual(move, "right")
 
+  def test_enemy_attack_map_marks_own_tail_contest(self):
+    snake = BestBattleSnake()
+
+    my_snake = {
+      "id": "me",
+      "name": "me",
+      "health": 90,
+      "length": 4,
+      "head": {"x": 3, "y": 3},
+      "body": [
+        {"x": 3, "y": 3},
+        {"x": 3, "y": 2},
+        {"x": 2, "y": 2},
+        {"x": 2, "y": 3},
+      ],
+    }
+
+    enemy = {
+      "id": "enemy",
+      "name": "enemy",
+      "health": 90,
+      "length": 6,
+      "head": {"x": 1, "y": 3},
+      "body": [
+        {"x": 1, "y": 3},
+        {"x": 1, "y": 2},
+        {"x": 1, "y": 1},
+        {"x": 0, "y": 1},
+        {"x": 0, "y": 2},
+        {"x": 0, "y": 3},
+      ],
+    }
+
+    attack_map = snake._build_enemy_attack_map(
+      my_snake=my_snake,
+      other_snakes=[enemy],
+      food_set=set(),
+      is_constrictor=False,
+      width=7,
+      height=7,
+      enemy_can_grow_cache={"enemy": False},
+    )
+
+    self.assertEqual(attack_map.get((2, 3)), 6)
+
+  def test_simulation_frees_enemy_tail_even_if_enemy_can_grow(self):
+    snake = BestBattleSnake()
+
+    future_body = [
+      {"x": 4, "y": 4},
+      {"x": 4, "y": 3},
+      {"x": 3, "y": 3},
+      {"x": 3, "y": 4},
+    ]
+    enemy = {
+      "id": "enemy",
+      "name": "enemy",
+      "health": 90,
+      "length": 4,
+      "head": {"x": 1, "y": 1},
+      "body": [
+        {"x": 1, "y": 1},
+        {"x": 1, "y": 0},
+        {"x": 0, "y": 0},
+        {"x": 0, "y": 1},
+      ],
+    }
+
+    blocked = snake._simulation_blocked(
+      future_body=future_body,
+      other_snakes=[enemy],
+      food_set={(2, 1)},
+      is_constrictor=False,
+      enemy_can_grow_cache={"enemy": True},
+    )
+
+    self.assertNotIn((0, 1), blocked)
+
+  def test_enemy_attack_map_allows_enemy_tail_move_when_enemy_can_grow(self):
+    snake = BestBattleSnake()
+
+    my_snake = {
+      "id": "me",
+      "name": "me",
+      "health": 90,
+      "length": 4,
+      "head": {"x": 6, "y": 6},
+      "body": [
+        {"x": 6, "y": 6},
+        {"x": 6, "y": 5},
+        {"x": 5, "y": 5},
+        {"x": 5, "y": 6},
+      ],
+    }
+
+    enemy = {
+      "id": "enemy",
+      "name": "enemy",
+      "health": 90,
+      "length": 4,
+      "head": {"x": 3, "y": 3},
+      "body": [
+        {"x": 3, "y": 3},
+        {"x": 3, "y": 2},
+        {"x": 2, "y": 2},
+        {"x": 2, "y": 3},
+      ],
+    }
+
+    attack_map = snake._build_enemy_attack_map(
+      my_snake=my_snake,
+      other_snakes=[enemy],
+      food_set={(4, 3)},
+      is_constrictor=False,
+      width=11,
+      height=11,
+      enemy_can_grow_cache={"enemy": True},
+    )
+
+    self.assertEqual(attack_map.get((2, 3)), 4)
+
+  def test_future_planning_prefers_non_trap_path(self):
+    snake = BestBattleSnake()
+
+    my_body = [
+      {"x": 3, "y": 3},
+      {"x": 3, "y": 2},
+      {"x": 2, "y": 2},
+      {"x": 2, "y": 3},
+    ]
+    enemy = {
+      "id": "enemy",
+      "name": "enemy",
+      "health": 90,
+      "length": 8,
+      "head": {"x": 0, "y": 0},
+      "body": [
+        {"x": 0, "y": 0},
+        {"x": 4, "y": 4},
+        {"x": 4, "y": 2},
+        {"x": 5, "y": 4},
+        {"x": 5, "y": 2},
+        {"x": 6, "y": 4},
+        {"x": 6, "y": 3},
+        {"x": 6, "y": 2},
+      ],
+    }
+
+    safe_moves = snake._legal_moves(
+      my_head=my_body[0],
+      my_body=my_body,
+      other_snakes=[enemy],
+      food_set=set(),
+      is_constrictor=False,
+      width=7,
+      height=7,
+    )
+
+    self.assertIn("left", safe_moves)
+    self.assertIn("right", safe_moves)
+
+    right_bonus = snake._future_rollout_bonus_for_move(
+      move="right",
+      safe_moves=safe_moves,
+      my_body=my_body,
+      other_snakes=[enemy],
+      food_set=set(),
+      is_constrictor=False,
+      width=7,
+      height=7,
+      enemy_can_grow_cache={"enemy": False},
+      depth=3,
+      branch_limit=2,
+      deadline=None,
+    )
+    left_bonus = snake._future_rollout_bonus_for_move(
+      move="left",
+      safe_moves=safe_moves,
+      my_body=my_body,
+      other_snakes=[enemy],
+      food_set=set(),
+      is_constrictor=False,
+      width=7,
+      height=7,
+      enemy_can_grow_cache={"enemy": False},
+      depth=3,
+      branch_limit=2,
+      deadline=None,
+    )
+
+    self.assertGreater(left_bonus, right_bonus)
+
 if __name__ == "__main__":
   unittest.main()