test: count en passant moves in perft

1 files changed, 21 insertions, 11 deletions

diff --git a/src/board.rs b/src/board.rs
index 58e4037..2cb4fcf 100644
--- a/src/board.rs
+++ b/src/board.rs
@@ -366,9 +366,9 @@ impl Board {
         self.ply -= 1;
     }
 
-    fn perft(&mut self, depth: u8, print: bool) -> (u64, u64, u64) {
+    fn perft(&mut self, depth: u8, print: bool) -> (u64, u64, u64, u64) {
         if depth == 0 {
-            return (1, 0, 0) // This a leaf, exactly one node
+            return (1, 0, 0, 0) // This a leaf, exactly one node
         }
         let color = self.color_to_move();
 
@@ -382,15 +382,23 @@ impl Board {
         let mut total = 0;
         let mut tactical = 0;
         let mut checks = 0;
+        let mut en_passants = 0;
 
         for mov in moves {
             let ep_target_before = self.ep_target.clone();
             let captured_piece = self.make_move(mov);
             // King can not be in check after our own move
             if !self.is_king_in_check(color) {
-                if captured_piece.is_some() {
-                    tactical += 1;
+                match mov.kind {
+                    MoveKind::Capture => {
+                        tactical += 1;
+                    }
+                    MoveKind::EnPassant => {
+                        en_passants += 1;
+                    }
+                    _ => {}
                 }
+
                 if self.is_king_in_check(color.flip()) {
                     checks += 1;
                 }
@@ -398,10 +406,11 @@ impl Board {
                     println!("{:?}", mov);
                     self.print();
                 }
-                let (children_total, children_tactical, children_checks) = self.perft(depth - 1, print);
+                let (children_total, children_tactical, children_checks, children_ep) = self.perft(depth - 1, print);
                 total += children_total;
                 tactical += children_tactical;
                 checks += children_checks;
+                en_passants += children_ep;
 
             }
             self.unmake_move(mov, captured_piece, ep_target_before);
@@ -411,7 +420,7 @@ impl Board {
             println!("Found {} nodes in this subtree (depth {})", total, depth);
         }
 
-        (total, tactical, checks)
+        (total, tactical, checks, en_passants)
     }
 
     fn is_square_attacked(&self, square: Square, attacker_color: Color) -> bool {
@@ -597,11 +606,12 @@ mod tests {
         let fen = String::from(DEFAULT_FEN);
         let mut board = Board::from_FEN(fen);
 
-        assert_eq!(board.perft(0, false), (1, 0, 0));
-        assert_eq!(board.perft(1, false), (20, 0, 0));
-        assert_eq!(board.perft(2, false), (400, 0, 0));
-        assert_eq!(board.perft(3, false), (8902, 34, 12));
-        // assert_eq!(board.perft(4, false), (197281, 1576, 469));
+        assert_eq!(board.perft(0, false), (1, 0, 0, 0));
+        assert_eq!(board.perft(1, false), (20, 0, 0, 0));
+        assert_eq!(board.perft(2, false), (400, 0, 0, 0));
+        assert_eq!(board.perft(3, false), (8902, 34, 12, 0));
+        assert_eq!(board.perft(4, false), (197281, 1576, 469, 0));
+        // assert_eq!(board.perft(5, false), (4865609, 82719, 27351));
     }
 
     #[test]