def trapped_piece(puzzle: Puzzle) -> bool:
for node in puzzle.mainline[1::2][1:]:
square = node.move.to_square
captured = node.parent.board().piece_at(square)
if captured and captured.piece_type != PAWN:
prev = node.parent
if prev.move.to_square == square:
square = prev.move.from_square
if util.is_trapped(prev.parent.board(), square):
return True
return False
def test_trapped(self):
self.assertFalse(
util.is_trapped(
chess.Board("q3k3/7p/8/4N2q/3PP3/4B3/8/4K2R b - - 0 1"),
parse_square("h5")))
self.assertTrue(
util.is_trapped(
chess.Board("q3k3/7p/8/4N2q/3PP3/4B3/7R/4K2R b - - 0 1"),
parse_square("h5")))
self.assertFalse(
util.is_trapped(
chess.Board("q3k3/7p/8/4N2b/3PP3/4B3/7R/4K2R b - - 0 1"),
parse_square("h5")))
self.assertFalse(
util.is_trapped(
chess.Board("4k3/7p/8/4N2q/3PP2p/4B3/8/4K3 b - - 0 1"),
parse_square("h5")))
self.assertTrue(
util.is_trapped(chess.Board("8/3P4/8/4N2b/7p/6N1/8/4K3 b - - 0 1"),
parse_square("h5")))