implement pawn movement logic and add unit tests for pawn moves

1 files changed, 54 insertions, 0 deletions

diff --git a/tests/pawn_moves_test.cpp b/tests/pawn_moves_test.cpp
new file mode 100644
index 0000000..47b8ceb
--- /dev/null
+++ b/tests/pawn_moves_test.cpp
@@ -0,0 +1,54 @@
+#include "moves.hpp"
+#include <cassert>
+
+bool HasMove(const std::vector<Move> &moves, int from, int to) {
+  Position expectedFrom = IndexToPosition(from);
+  Position expectedTo = IndexToPosition(to);
+  for (const Move &move : moves) {
+    if (move.From.rank == expectedFrom.rank &&
+        move.From.file == expectedFrom.file && move.To.rank == expectedTo.rank &&
+        move.To.file == expectedTo.file) {
+      return true;
+    }
+  }
+  return false;
+}
+
+int CountMovesFrom(const std::vector<Move> &moves, int from) {
+  Position expected = IndexToPosition(from);
+  int count = 0;
+  for (const Move &move : moves) {
+    if (move.From.rank == expected.rank && move.From.file == expected.file) {
+      count++;
+    }
+  }
+  return count;
+}
+
+int main() {
+  board white{};
+  white.turn = true;
+  white.pieces[52] = createPiece(PAWN, true);  // e2
+  white.pieces[43] = createPiece(ROOK, false); // d3
+  white.pieces[45] = createPiece(ROOK, true);  // f3
+
+  std::vector<Move> whiteMoves = GetLegalMoves(&white);
+  assert(CountMovesFrom(whiteMoves, 52) == 3);
+  assert(HasMove(whiteMoves, 52, 44)); // e2-e3
+  assert(HasMove(whiteMoves, 52, 36)); // e2-e4
+  assert(HasMove(whiteMoves, 52, 43)); // e2xd3
+
+  white.pieces[44] = createPiece(KING, true); // block e3 and e4
+  std::vector<Move> blockedMoves = GetLegalMoves(&white);
+  assert(CountMovesFrom(blockedMoves, 52) == 1);
+  assert(HasMove(blockedMoves, 52, 43)); // capture remains legal
+
+  board black{};
+  black.turn = false;
+  black.pieces[12] = createPiece(PAWN, false); // e7
+
+  std::vector<Move> blackMoves = GetLegalMoves(&black);
+  assert(CountMovesFrom(blackMoves, 12) == 2);
+  assert(HasMove(blackMoves, 12, 20)); // e7-e6
+  assert(HasMove(blackMoves, 12, 28)); // e7-e5
+}