From 869e7a11ffc832afbbc7fb999ffdb643db109bed Mon Sep 17 00:00:00 2001
From: eug-vs <eugene@eug-vs.xyz>
Date: Mon, 23 Jan 2023 10:56:50 +0300
Subject: test: count checks in perft

---
 src/board.rs | 30 ++++++++++++++++++------------
 1 file changed, 18 insertions(+), 12 deletions(-)

diff --git a/src/board.rs b/src/board.rs
index 7b17aad..7295b5f 100644
--- a/src/board.rs
+++ b/src/board.rs
@@ -286,9 +286,9 @@ impl Board {
         self.ply -= 1;
     }
 
-    fn perft(&mut self, depth: u8, print: bool) -> (u64, u64) {
+    fn perft(&mut self, depth: u8, print: bool) -> (u64, u64, u64) {
         if depth == 0 {
-            return (1, 0) // This a leaf, exactly one node
+            return (1, 0, 0) // This a leaf, exactly one node
         }
         let color = self.color_to_move();
 
@@ -301,21 +301,27 @@ impl Board {
 
         let mut total = 0;
         let mut tactical = 0;
+        let mut checks = 0;
 
         for mov in moves {
             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;
+                }
+                if self.is_king_in_check(color.flip()) {
+                    checks += 1;
+                }
                 if print {
                     println!("{:?}", mov);
                     self.print();
                 }
-                if captured_piece.is_some() {
-                    tactical += 1;
-                }
-                let (children_total, children_tactical) = self.perft(depth - 1, print);
+                let (children_total, children_tactical, children_checks) = self.perft(depth - 1, print);
                 total += children_total;
                 tactical += children_tactical;
+                checks += children_checks;
+
             }
             self.unmake_move(mov, captured_piece);
         }
@@ -324,7 +330,7 @@ impl Board {
             println!("Found {} nodes in this subtree (depth {})", total, depth);
         }
 
-        (total, tactical)
+        (total, tactical, checks)
     }
 
     fn is_square_attacked(&self, square: Square, attacker_color: Color) -> bool {
@@ -510,11 +516,11 @@ mod tests {
         let fen = String::from(DEFAULT_FEN);
         let mut board = Board::from_FEN(fen);
 
-        assert_eq!(board.perft(0, false), (1, 0));
-        assert_eq!(board.perft(1, false), (20, 0));
-        assert_eq!(board.perft(2, false), (400, 0));
-        assert_eq!(board.perft(3, false), (8902, 34));
-        // assert_eq!(board.perft(4, false), (197281, 1576));
+        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));
     }
 
     #[test]
-- 
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