[board, position] Simplify check methods

Only one check-testing method, Board::is_in_check(), that tests if the current
active player is in check. It doesn't make sense to test if the non-active player
is in check.

board/src/check.rs

@@ -5,18 +5,10 @@ use chessfriend_bitboard::BitBoard;
 use chessfriend_core::{Color, Piece};
 
 impl Board {
+    /// Return whether the active color is in check.
     #[must_use]
-    pub fn active_color_is_in_check(&self) -> bool {
+    pub fn is_in_check(&self) -> bool {
-        self.unwrapped_color_is_in_check(self.active_color())
+        let color = self.active_color();
-    }
-
-    #[must_use]
-    pub fn color_is_in_check(&self, color: Option<Color>) -> bool {
-        self.unwrapped_color_is_in_check(self.unwrap_color(color))
-    }
-
-    #[must_use]
-    pub fn unwrapped_color_is_in_check(&self, color: Color) -> bool {
         let king = self.king_bitboard(color);
         let opposing_sight = self.opposing_sight(color);
         (king & opposing_sight).is_populated()
@@ -39,7 +31,7 @@ mod tests {
             Black Rook on F3,
         );
 
-        assert!(board.unwrapped_color_is_in_check(Color::White));
+        assert!(board.is_in_check());
     }
 
     #[test]
@@ -49,6 +41,6 @@ mod tests {
             Black Rook on B4,
         );
 
-        assert!(!board.unwrapped_color_is_in_check(Color::White));
+        assert!(!board.is_in_check());
     }
 }

position/src/position.rs

@@ -129,7 +129,7 @@ impl Position {
                     );
                 });
 
-            let move_is_legal = !test_board.color_is_in_check(Some(active_color_before_move));
+            let move_is_legal = !test_board.is_in_check();
 
             test_board.unmake_move(&record).unwrap_or_else(|err| {
                 panic!(

position/tests/peterellisjones.rs

@@ -107,7 +107,7 @@ fn en_passant_check_capture() {
         White Pawn on D4,
     ], D3);
 
-    assert!(pos.board().active_color_is_in_check());
+    assert!(pos.board().is_in_check());
 
     let generated_moves: HashSet<_> = pos.all_legal_moves(Some(Color::Black)).collect();
 
@@ -123,7 +123,7 @@ fn en_passant_check_block() {
         White Queen on F1,
     ], D3);
 
-    assert!(pos.board().active_color_is_in_check());
+    assert!(pos.board().is_in_check());
 
     let generated_moves: HashSet<_> = pos.all_legal_moves(Some(Color::Black)).collect();
 
@@ -139,7 +139,7 @@ fn pinned_pieces_rook_cannot_move_out_of_pin() {
         White King on C1,
     ]);
 
-    assert!(!pos.board().active_color_is_in_check());
+    assert!(!pos.board().is_in_check());
 
     let rook_moves: HashSet<_> = pos.all_legal_moves(None).collect();