test: some evaluation sanity checks

1 files changed, 119 insertions, 3 deletions

diff --git a/src/board/engine.rs b/src/board/engine.rs
index 65851cf..53d2564 100644
--- a/src/board/engine.rs
+++ b/src/board/engine.rs
@@ -195,7 +195,7 @@ impl Board {
 
         let king_tropism_penalty = self.king_tropism(color) - self.king_tropism(opponent_color);
 
-        material_advantage + 0.1 * mobility_advantage - 0.5 * pawn_structure_penalty + king_tropism_penalty * opponent_material / 100.0
+        material_advantage + 0.1 * mobility_advantage - 0.5 * pawn_structure_penalty + king_tropism_penalty * opponent_material / 150.0
     }
 
     /// Evaluate move for move ordering, prioritizing efficient captures
@@ -453,9 +453,125 @@ mod tests {
     #[test]
     fn material() {
         let board = Board::new();
-        assert_eq!(board.material(Color::Black), 38.0);
-        assert_eq!(board.material(Color::White), 38.0);
+        assert_eq!(board.material(Color::Black), 40.0);
+        assert_eq!(board.material(Color::White), 40.0);
 
     }
 
+    mod evaluation {
+        use crate::{moves::{Move, MoveKind}, square::Square};
+
+        use super::*;
+
+        #[test]
+        fn initial_eval() {
+            let board = Board::new();
+            assert_eq!(board.evaluate(None), 0.0);
+        }
+
+        #[test]
+        fn king_tropism() {
+            let mut board = Board::new();
+            board.make_move(Move { source: Square::D1, target: Square::F5, kind: MoveKind::Quiet });
+            let score = board.evaluate(None);
+            board.print();
+            println!("Score {}", score);
+
+            assert!(score < 0.0);
+            assert!(score > -1.0);
+        }
+
+        #[test]
+        fn white_winning() {
+            let fen = String::from("8/5pk1/6p1/R4b1p/3P4/1P2N3/P1r2PPP/R5K1 b - - 1 27");
+            let board = Board::from_FEN(fen);
+            let score = board.evaluate(None);
+            board.print();
+            println!("Score {}", score);
+
+            assert!(score > 7.0);
+        }
+
+        #[test]
+        fn black_winning() {
+            let fen = String::from("8/p7/1k4K1/8/4P3/8/PP5r/8 b - - 1 38");
+            let board = Board::from_FEN(fen);
+            let score = board.evaluate(None);
+            board.print();
+            println!("Score {}", score);
+
+            assert!(score < -4.0);
+        }
+
+        #[test]
+        fn encourage_center_pawns() {
+            let score1 = {
+                let fen = String::from("rnbqkbnr/pppp1ppp/8/4p3/4P3/8/PPPP1PPP/RNBQKBNR w KQkq - 0 2");
+                let board = Board::from_FEN(fen);
+                let score = board.evaluate(None);
+                board.print();
+                println!("Score {}", score);
+                score
+            };
+
+            let score2 = {
+                let fen = String::from("rnbqkbnr/pppp1ppp/8/4p3/2P5/8/PP1PPPPP/RNBQKBNR w KQkq - 0 2");
+                let board = Board::from_FEN(fen);
+                let score = board.evaluate(None);
+                board.print();
+                println!("Score {}", score);
+                score
+            };
+
+            assert!(score1 > score2);
+        }
+
+        #[test]
+        fn discourage_edge_knights() {
+            let score1 = {
+                let fen = String::from("r1bqkbnr/pppp1ppp/2n5/4p3/4P3/5N2/PPPP1PPP/RNBQKB1R w KQkq - 2 3");
+                let board = Board::from_FEN(fen);
+                let score = board.evaluate(None);
+                board.print();
+                println!("Score {}", score);
+                score
+            };
+
+            let score2 = {
+                let fen = String::from("r1bqkbnr/pppp1ppp/2n5/4p3/4P3/7N/PPPP1PPP/RNBQKB1R w KQkq - 2 3");
+                let board = Board::from_FEN(fen);
+                let score = board.evaluate(None);
+                board.print();
+                println!("Score {}", score);
+                score
+            };
+
+            assert!(score1 > score2);
+        }
+
+        #[test]
+        fn mirrored_evaluation() {
+            let score1 = {
+                let fen = String::from("r3k2r/Pppp1ppp/1b3nbN/nP6/BBP1P3/q4N2/Pp1P2PP/R2Q1RK1 w kq - 0 1");
+                let board = Board::from_FEN(fen);
+                let score = board.evaluate(None);
+                board.print();
+                println!("Score {}", score);
+                score
+            };
+
+            let score2 = {
+                let fen = String::from("r2q1rk1/pP1p2pp/Q4n2/bbp1p3/Np6/1B3NBn/pPPP1PPP/R3K2R b KQ - 0 1 ");
+                let mut board = Board::from_FEN(fen);
+                board.ply += 1; // TODO: remove me when FEN parsing includes side to move
+                let score = board.evaluate(None);
+                board.print();
+                println!("Score {}", score);
+                score
+            };
+
+            assert_eq!(score1.abs(), score2.abs());
+        }
+    }
+
 }