import ctypes from binding.python_c_ffi import Board from binding.python_c_ffi import Move from test.base import ChessLibTestBase MAX_MOVES = 256 class TestPseudoMoveGeneration(ChessLibTestBase): def run_subtests(self, cases, move_function, captures_only=None): for fen, expected, msg in cases: with self.subTest(msg=msg, fen=fen): cnt = ctypes.c_int(0) moves = (Move * MAX_MOVES)() b = Board() self.chess_ffi.load_fen(b , fen) if captures_only is not None: move_function(b, moves, cnt, captures_only) else: # Account for pawn move gen. move_function(b, moves, cnt) self.assertEqual(expected, cnt.value) def test_knight_move_gen(self): all_move_types = [ ("8/8/8/8/3N4/8/8/8 w - - 0 1", 8, "center d4: 8 moves"), ("8/8/8/8/N7/8/8/8 w - - 0 1", 4, "edge a4: 4 moves"), ("8/8/8/8/8/8/8/N7 w - - 0 1", 2, "corner a1: 2 moves"), ("8/8/8/8/8/8/8/1N6 w - - 0 1", 3, "b1: 3 moves"), # own pieces on destinations reduce count ("8/8/8/5P2/3N4/1P6/2P5/8 w - - 0 1", 5, "d4 with own pawns on f5,b3,c2 -> 8-3=5"), # two knights ("8/8/8/8/8/8/8/1N4N1 w - - 0 1", 6, "b1 & g1, empty board: 3+3"), # all 8 destinations occupied by black (still 8 total moves, all as captures) ("8/8/2p1p3/1p3p2/3N4/1p3p2/2p1p3/8 w - - 0 1", 8, "enemy on all 8 targets"), # corner with one capture and one friendly block ("8/8/8/8/8/1p6/2P5/N7 w - - 0 1", 1, "a1, b3 black (capture), c2 white (blocked)"), ] captures_only = [ ("8/8/8/8/3N4/8/8/8 w - - 0 1", 0, "center d4 but no enemies"), ("8/8/2p5/1p6/3N4/5p2/8/8 w - - 0 1", 3, "d4 capturing c6,b5,f3"), ("8/8/8/8/3N4/1P3p2/4P3/8 w - - 0 1", 1, "d4 with f3 black (1 cap), b3/e2 white (not capturable)"), ("8/8/2p1p3/1p3p2/3N4/1p3p2/2p1p3/8 w - - 0 1", 8, "d4 with all 8 targets black: 8 captures"), ] self.run_subtests(all_move_types, self.chess_ffi._c_gen_knight_moves, captures_only=False) self.run_subtests(captures_only, self.chess_ffi._c_gen_knight_moves, captures_only=True) def test_bishop_move_gen(self): cases_bishop_all = [ ("8/8/8/8/3B4/8/8/8 w - - 0 1", 13, "center d4: 13 moves"), ("8/8/8/8/B7/8/8/8 w - - 0 1", 7, "edge a4: 7 moves"), ("8/8/8/8/8/8/8/B7 w - - 0 1", 7, "corner a1: 7 moves"), ("8/8/8/8/8/8/8/1B6 w - - 0 1", 7, "b1: 7 moves"), # all four diagonals blocked immediately by own pieces -> 0 ("8/8/8/2P1P3/3B4/2P1P3/8/8 w - - 0 1", 0, "d4 with white pawns on c3,e3,c5,e5"), # all four diagonals have a black piece on the first square -> 4 (all captures) ("8/8/8/2p1p3/3B4/2p1p3/8/8 w - - 0 1", 4, "d4 with black pawns on c3,e3,c5,e5"), # mixed blockers: NE own on f6, SW capture on b2, SE capture on e3, NW open ("8/8/1p3P2/8/3B4/4p3/1p6/8 w - - 0 1", 6, ""), ] cases_bishop_caps = [ ("8/8/8/8/3B4/8/8/8 w - - 0 1", 0, "no enemies to capture"), # first squares on all rays are enemies → 4 captures ("8/8/8/2p1p3/3B4/2p1p3/8/8 w - - 0 1", 4, "adjacent caps on c3,e3,c5,e5"), # enemies at far ends on each ray → still 4 captures (one per ray) ("7p/p7/8/8/3B4/8/8/p5p1 w - - 0 1", 4, "targets h8,a7,g1,a1"), # mixed: only two rays have a capture ("8/8/1p3P2/8/3B4/2P5/5p2/8 w - - 0 1", 2, "d4: NW capture b6, SE capture f2; NE/SW blocked by own"), ] self.run_subtests(cases_bishop_all, self.chess_ffi._c_gen_bishop_moves, captures_only=False) self.run_subtests(cases_bishop_caps, self.chess_ffi._c_gen_bishop_moves, captures_only=True) def test_rook_move_gen(self): cases_rook_all = [ ("8/8/8/8/3R4/8/8/8 w - - 0 1", 14, "center d4: 14 moves on empty board"), ("8/8/8/8/R7/8/8/8 w - - 0 1", 14, "edge a4: still 14 on empty board"), ("8/8/8/8/8/8/8/R7 w - - 0 1", 14, "corner a1: 14 on empty board"), # all four adjacents are own pieces → no squares available ("8/8/8/3P4/2PRP3/3P4/8/8 w - - 0 1", 0, "d4 with white pawns on c4,d5,e4,d3 (fully blocked)"), # all four adjacents are enemy pieces → exactly 4 captures ("8/8/8/3p4/2pRp3/3p4/8/8 w - - 0 1", 4, "d4 with black pawns on c4,d5,e4,d3 (adjacent captures)"), # mixed: horizontal blocked by own, vertical has one capture each way ("8/8/3p4/8/2PRP3/8/3p4/8 w - - 0 1", 4, "d4; own c4/e4 block left/right; captures at d5,d3"), # two rooks on a1 and h1 block each other along rank 1 ("8/8/8/8/8/8/8/R6R w - - 0 1", 26, "a1 and h1: 13 each (not 14) because they block each other on rank"), ] cases_rook_caps = [ ("8/8/8/8/3R4/8/8/8 w - - 0 1", 0, "no enemies at all"), # adjacent enemies in all 4 directions → 4 captures ("8/8/8/3p4/2pRp3/3p4/8/8 w - - 0 1", 4, "adjacent captures at c4,d5,e4,d3"), # two far enemies on clear rays → 2 captures (h4 and d8) ("3r4/8/8/8/3R3r/8/8/8 w - - 0 1", 2, "captures on d8 and h4"), # mixed: own pieces block two rays; captures on the other two (a4 and d1) ("8/8/8/3P4/p2RP3/8/8/3p4 w - - 0 1", 2, "own on d5,e4; captures on a4 and d1"), ] self.run_subtests(cases_rook_all, self.chess_ffi._c_gen_rook_moves, captures_only=False) self.run_subtests(cases_rook_caps, self.chess_ffi._c_gen_rook_moves, captures_only=True) def test_queen_move_gen(self): cases_queen_all = [ ("8/8/8/8/3Q4/8/8/8 w - - 0 1", 27, "center d4: rook(14)+bishop(13)"), ("8/8/8/8/Q7/8/8/8 w - - 0 1", 21, "edge a4: 14+7"), ("8/8/8/8/8/8/8/Q7 w - - 0 1", 21, "corner a1: 14+7"), ("8/8/8/8/8/8/8/1Q6 w - - 0 1", 21, "b1: 14+7"), # all 8 adjacent squares are friendly ⇒ blocked immediately on all rays ("8/8/8/2PPP3/2PQP3/2PPP3/8/8 w - - 0 1", 0, "d4 with white pawns on c3,d3,e3,c4,e4,c5,d5,e5"), # all 8 adjacent squares are enemies ⇒ exactly 8 captures (one per ray), no further squares ("8/8/8/2p1p3/2pQp3/2p1p3/8/8 w - - 0 1", 13, "d4 with black pawns adjacent on all rays"), # only horizontal blocked by own pieces at c4/e4; vertical+diagonals open ("8/8/8/8/2PQP3/8/8/8 w - - 0 1", 20, "d4, own at c4,e4: rook loses 7→7 (up+down only), bishop 13 ⇒ 20"), # two queens on a1 & h1 block each other along rank 1 ("8/8/8/8/8/8/8/Q6Q w - - 0 1", 40, "a1 & h1: each 21→20 due to mutual block ⇒ 40 total"), ] cases_queen_caps = [ ("8/8/8/8/3Q4/8/8/8 w - - 0 1", 0, "no enemies to capture"), # adjacent enemies only → 6 captures ("8/8/8/2p1p3/2pQp3/2p1p3/8/8 w - - 0 1", 6, "adjacent caps on all rays"), # adjacent enemies only → 8 captures ("8/8/8/2ppp3/2pQp3/2ppp3/8/8 w - - 0 1", 8, "adjacent caps on all rays"), # far targets on two rook rays (d8 and h4) + friendly blocking b1 ("3r4/8/8/8/1P1Q3r/8/8/8 w - - 0 1", 2, "captures on d8 and h4; b4 friend blocks left; no other enemies"), # mixed: captures on two diagonals only ("7p/p7/8/8/3Q4/8/8/p5p1 w - - 0 1", 4, "diagonal targets a1,a7,g1,h8 (4 captures)"), ] self.run_subtests(cases_queen_all, self.chess_ffi._c_gen_queen_moves, captures_only=False) self.run_subtests(cases_queen_caps, self.chess_ffi._c_gen_queen_moves, captures_only=True) def test_king_move_gen(self): cases_king_all = [ ("8/8/8/8/3K4/8/8/8 w - - 0 1", 8, "center d4: 8 moves"), ("8/8/8/8/K7/8/8/8 w - - 0 1", 5, "edge a4: 5 moves"), ("8/8/8/8/8/8/8/K7 w - - 0 1", 3, "corner a1: 3 moves"), # all eight adjacent squares are WHITE pieces → 0 ("8/8/8/2PPP3/2PKP3/2PPP3/8/8 w - - 0 1", 0, "surrounded by own"), # all eight adjacent squares are BLACK pieces → 8 (all captures) ("8/8/8/2ppp3/2pKp3/2ppp3/8/8 w - - 0 1", 8, "surrounded by enemies"), # mixed: own block east/west; captures NE & SE; rest quiet ("8/8/8/2p5/2PKP3/4p3/8/8 w - - 0 1", 6, "d4: caps c5,e3; quiet d5,d3,c3,e5"), ] cases_king_caps = [ ("8/8/8/8/3K4/8/8/8 w - - 0 1", 0, "no enemies"), # eight adjacent enemies → 8 captures ("8/8/8/2ppp3/2pKp3/2ppp3/8/8 w - - 0 1", 8, "all adjacent caps"), # edge a1 with only b2 enemy → 1 capture ("8/8/8/8/8/8/1p6/K7 w - - 0 1", 1, "a1: only Kxb2"), # mixed: same as above mixed case → 2 captures ("8/8/8/2p5/2PKP3/4p3/8/8 w - - 0 1", 2, "captures c5 & e3"), ] cases_king_castle_white = [ ("8/8/8/8/8/8/8/R3K2R w KQ - 0 1", 7, "e1 with KQ rights, empty lanes: 5 king steps + O-O + O-O-O"), ("8/8/8/8/8/8/8/4K2R w K - 0 1", 6, "e1 with K only: 5 steps + O-O"), ("8/8/8/8/8/8/8/R3K3 w Q - 0 1", 6, "e1 with Q only: 5 steps + O-O-O"), # blocked kingside (f1 occupied) → only O-O-O available ("8/8/8/8/8/8/8/R3KB1R w KQ - 0 1", 5, "f1 blocked by own piece; queen-side castle only"), # blocked queenside (d1 occupied) → only O-O available ("8/8/8/8/8/8/8/R2BK2R w KQ - 0 1", 5, "d1 blocked by own piece; king-side castle only"), # both sides blocked (d1 and f1 occupied) → no castles, just 5 normal moves ("8/8/8/8/8/8/8/R2BKB1R w KQ - 0 1", 3, "both lanes blocked; no castles"), ] cases_king_castle_black = [ ("r3k2r/8/8/8/8/8/8/8 b kq - 0 1", 7, "e8 with kq rights, empty lanes: 5 steps + O-O + O-O-O"), ("4k2r/8/8/8/8/8/8/8 b k - 0 1", 6, "e8 with k only: 5 steps + O-O"), ("r3k3/8/8/8/8/8/8/8 b q - 0 1", 6, "e8 with q only: 5 steps + O-O-O"), # blocked kingside (f8 occupied) → only O-O-O available ("r3kb1r/8/8/8/8/8/8/8 b kq - 0 1", 5, "f8 blocked; only queen-side castle"), # blocked queenside (d8 occupied) → only O-O available ("r2bk2r/8/8/8/8/8/8/8 b kq - 0 1", 5, "d8 blocked; only king-side castle"), ] self.run_subtests(cases_king_all, self.chess_ffi._c_gen_king_moves, captures_only=False) self.run_subtests(cases_king_castle_white, self.chess_ffi._c_gen_king_moves, captures_only=False) self.run_subtests(cases_king_caps, self.chess_ffi._c_gen_king_moves, captures_only=True) self.run_subtests(cases_king_castle_black, self.chess_ffi._c_gen_king_moves, captures_only=False) def test_quiet_pawn_pushes_white(self): cases = [ ("8/pppppppp/8/8/8/8/PPPPPPPP/8 w - - 0 1", 16, "open ranks"), ("8/8/8/8/8/8/P7/8 w - - 0 1", 2, "single pawn open"), ("8/8/8/8/8/p7/P7/8 w - - 0 1", 0, "blocked single enemy"), ("8/8/8/8/8/n7/P7/8 w - - 0 1", 0, "blocked single friendly"), # Although legal move, we have a separate function that calculates this move type. ("8/9P/8/8/8/8/8/8 w - - 0 1", 0, "no promotion push"), ] self.run_subtests(cases, self.chess_ffi._c_gen_white_pawn_quiet_pushes) def test_quiet_pawn_promotions_white(self): cases = [ ("8/PPPPPPPP/8/8/8/8/8/8 w - - 0 1", 32, "all open on 7th rank"), ("8/8/7P/8/8/8/8/8 w - - 0 1", 0, "no promotions"), ("7n/7P/8/8/8/8/8/8 w - - 0 1", 0, "blocked by enemy"), ("7N/7P/8/8/8/8/8/8 w - - 0 1", 0, "blocked by friendly"), ] self.run_subtests(cases, self.chess_ffi._c_gen_white_pawn_push_promotions) def test_capture_pawn_promotions_white(self): cases = [ ("6n1/7P/8/8/8/8/8/8 w - - 0 1", 4, "one capture"), ("5n1n/6P1/8/8/8/8/8/8 w - - 0 1", 8, "two captures"), ("8/7P/8/8/8/8/8/8 w - - 0 1", 0, "no capture"), ] self.run_subtests(cases, self.chess_ffi._c_gen_white_pawn_capture_promotions) def test_capture_pawn_white(self): cases = [ # normal diagonal captures ("8/8/8/3n4/4P3/8/8/8 w - - 0 1", 1, "e4xd5"), ("8/8/8/3n1n2/4P3/8/8/8 w - - 0 1", 2, "e4xd5 and e4xf5"), ("8/8/8/1p6/P7/8/8/8 w - - 0 1", 1, "edge file: a4xb5"), ("8/7P/8/8/8/8/8/8 w - - 0 1", 0, "no capture"), # en passant ("8/8/8/3pP3/8/8/8/8 w - d6 0 1", 1, "EP available: e5xd6 e.p. (black pawn on d5)"), ("8/8/5n2/3pP3/8/8/8/8 w - d6 0 1", 2, "EP e5xd6 and normal e5xf6"), ("8/8/8/3p4/8/4P3/8/8 w - d6 0 1", 0, "EP square present but no white pawn can take"), ] self.run_subtests(cases, self.chess_ffi._c_gen_white_pawn_captures)