diff --git a/lib/Board.cpp b/lib/Board.cpp
index e0950e4..c5d8c0f 100644
--- a/lib/Board.cpp
+++ b/lib/Board.cpp
@@ -60,7 +60,7 @@ static Cell cellAtPosition(GridPosition point) {
 }
 
 bool isWalkableForPacMan(GridPosition point) {
-  return cellAtPosition(point) != Cell::wall;
+  return cellAtPosition(point) != Cell::wall && cellAtPosition(point) != Cell::pen;
 }
 
 bool isWalkableForGhost(GridPosition point, GridPosition origin, bool isEyes) {
@@ -79,6 +79,26 @@ bool isPortal(GridPosition point, Direction direction) {
          (cellAtPosition(point) == Cell::right_portal && direction == Direction::RIGHT);
 }
 
+bool isIntersection(GridPosition point) {
+  if (!isWalkableForPacMan(point) || cellAtPosition(point) == Cell::left_portal || cellAtPosition(point) == Cell::right_portal) {
+    return false;
+  }
+
+  const GridPosition right{ point.x + 1, point.y };
+  const bool rightWalkable = isWalkableForPacMan(right);
+
+  const GridPosition left{ point.x - 1, point.y };
+  const bool leftWalkable = isWalkableForPacMan(left);
+
+  const GridPosition top{ point.x, point.y - 1 };
+  const bool topWalkable = isWalkableForPacMan(top);
+
+  const GridPosition bottom{ point.x, point.y + 1 };
+  const bool bottomWalkable = isWalkableForPacMan(bottom);
+
+  return (topWalkable && rightWalkable) || (rightWalkable && bottomWalkable) || (bottomWalkable && leftWalkable) || (leftWalkable && topWalkable);
+}
+
 GridPosition teleport(GridPosition point) {
   size_t right = COLUMNS - 1;
   size_t left = 0;
@@ -124,26 +144,4 @@ std::vector<GridPosition> initialSuperPelletPositions() {
   return positions;
 }
 
-// AI
-
-bool isIntersection(GridPosition point) {
-  if (!isWalkableForPacMan(point) || cellAtPosition(point) == Cell::left_portal || cellAtPosition(point) == Cell::right_portal) {
-    return false;
-  }
-
-  const GridPosition right{ point.x + 1, point.y };
-  const bool rightWalkable = isWalkableForPacMan(right);
-
-  const GridPosition left{ point.x - 1, point.y };
-  const bool leftWalkable = isWalkableForPacMan(left);
-
-  const GridPosition top{ point.x, point.y - 1 };
-  const bool topWalkable = isWalkableForPacMan(top);
-
-  const GridPosition bottom{ point.x, point.y + 1 };
-  const bool bottomWalkable = isWalkableForPacMan(bottom);
-
-  return (topWalkable && rightWalkable) || (rightWalkable && bottomWalkable) || (bottomWalkable && leftWalkable) || (leftWalkable && topWalkable);
-}
-
 } // namespace pacman
diff --git a/lib/include/Board.hpp b/lib/include/Board.hpp
index 56829c3..ebacf0a 100644
--- a/lib/include/Board.hpp
+++ b/lib/include/Board.hpp
@@ -12,10 +12,11 @@ bool isWalkableForPacMan(GridPosition point);
 bool isWalkableForGhost(GridPosition point, GridPosition origin, bool isEyes);
 bool isInPen(GridPosition point);
 bool isPortal(GridPosition point, Direction direction);
+bool isIntersection(GridPosition point);
+
 GridPosition teleport(GridPosition point);
 
 std::vector<GridPosition> initialPelletPositions();
-
 std::vector<GridPosition> initialSuperPelletPositions();
 
 inline Position penDoorPosition() {
@@ -25,6 +26,4 @@ inline Position initialPacManPosition() {
   return { 13.5, 23 };
 }
 
-bool isIntersection(GridPosition point);
-
 } // namespace pacman
diff --git a/test/testBoard.cpp b/test/testBoard.cpp
new file mode 100644
index 0000000..c9c6fb5
--- /dev/null
+++ b/test/testBoard.cpp
@@ -0,0 +1,68 @@
+#include "Board.hpp"
+#include <catch2/catch.hpp>
+
+// These tests assume a static game board.
+
+TEST_CASE("Is walkable for Pac-Man", "[board]") {
+  REQUIRE_FALSE(pacman::isWalkableForPacMan(pacman::GridPosition{ 0, 0 }));   // wall
+  REQUIRE_FALSE(pacman::isWalkableForPacMan(pacman::GridPosition{ 27, 0 }));  // wall
+  REQUIRE_FALSE(pacman::isWalkableForPacMan(pacman::GridPosition{ 0, 30 }));  // wall
+  REQUIRE_FALSE(pacman::isWalkableForPacMan(pacman::GridPosition{ 27, 30 })); // wall
+  REQUIRE_FALSE(pacman::isWalkableForPacMan(pacman::GridPosition{ 11, 13 })); // pen
+
+  REQUIRE(pacman::isWalkableForPacMan(pacman::GridPosition{ 1, 1 }));   // pellet
+  REQUIRE(pacman::isWalkableForPacMan(pacman::GridPosition{ 1, 3 }));   // power pellet
+  REQUIRE(pacman::isWalkableForPacMan(pacman::GridPosition{ 1, 14 }));  // nothing
+  REQUIRE(pacman::isWalkableForPacMan(pacman::GridPosition{ 0, 14 }));  // portal left
+  REQUIRE(pacman::isWalkableForPacMan(pacman::GridPosition{ 27, 14 })); // portal right
+}
+
+TEST_CASE("Is walkable for Ghost", "[board]") {
+  const pacman::GridPosition pen = pacman::GridPosition{ 11, 13 };
+  const pacman::GridPosition outside = pacman::GridPosition{ 1, 1 };
+
+  // wall check
+  REQUIRE_FALSE(pacman::isWalkableForGhost(pacman::GridPosition{ 0, 0 }, outside, false));   // wall
+  REQUIRE_FALSE(pacman::isWalkableForGhost(pacman::GridPosition{ 27, 0 }, outside, false));  // wall
+  REQUIRE_FALSE(pacman::isWalkableForGhost(pacman::GridPosition{ 0, 30 }, outside, false));  // wall
+  REQUIRE_FALSE(pacman::isWalkableForGhost(pacman::GridPosition{ 27, 30 }, outside, false)); // wall
+
+  // eyes can walk anywhere except walls
+  REQUIRE(pacman::isWalkableForGhost(pacman::GridPosition{ 11, 13 }, outside, true)); // pen
+  REQUIRE(pacman::isWalkableForGhost(pacman::GridPosition{ 1, 1 }, outside, true));   // pellet
+  REQUIRE(pacman::isWalkableForGhost(pacman::GridPosition{ 1, 3 }, outside, true));   // power pellet
+  REQUIRE(pacman::isWalkableForGhost(pacman::GridPosition{ 1, 14 }, outside, true));  // nothing
+  REQUIRE(pacman::isWalkableForGhost(pacman::GridPosition{ 0, 14 }, outside, true));  // portal left
+  REQUIRE(pacman::isWalkableForGhost(pacman::GridPosition{ 27, 14 }, outside, true)); // portal right
+
+  // can only walk in pen if that is your origin or current location
+  REQUIRE_FALSE(pacman::isWalkableForGhost(pacman::GridPosition{ 11, 13 }, outside, false)); // in pen, origin outside
+  REQUIRE(pacman::isWalkableForGhost(pacman::GridPosition{ 1, 1 }, outside, false));         // outside, origin outside
+  REQUIRE(pacman::isWalkableForGhost(pacman::GridPosition{ 1, 1 }, pen, false));             // outside, origin pen
+  REQUIRE(pacman::isWalkableForGhost(pacman::GridPosition{ 11, 13 }, pen, false));           // in pen, origin pen
+}
+
+TEST_CASE("Is portal", "[board]") {
+  const pacman::GridPosition portalRight = pacman::GridPosition{ 27, 14 };
+  const pacman::GridPosition portalLeft = pacman::GridPosition{ 0, 14 };
+
+  REQUIRE(pacman::isPortal(portalRight, pacman::Direction::RIGHT));      // right into right portal
+  REQUIRE(pacman::isPortal(portalLeft, pacman::Direction::LEFT));        // left into left portal
+  REQUIRE_FALSE(pacman::isPortal(portalRight, pacman::Direction::LEFT)); // left into right portal
+  REQUIRE_FALSE(pacman::isPortal(portalLeft, pacman::Direction::RIGHT)); // right into left portal
+}
+
+TEST_CASE("Teleport", "[board]") {
+  const pacman::GridPosition portalRight = pacman::GridPosition{ 27, 14 };
+  const pacman::GridPosition portalLeft = pacman::GridPosition{ 0, 14 };
+
+  if (pacman::isPortal(portalRight, pacman::Direction::RIGHT)) {
+    const pacman::GridPosition result = pacman::teleport(portalRight);
+    REQUIRE(result.x == portalLeft.x);
+  }
+
+  if (pacman::isPortal(portalLeft, pacman::Direction::LEFT)) {
+    const pacman::GridPosition result = pacman::teleport(portalLeft);
+    REQUIRE(result.x == portalRight.x);
+  }
+}
\ No newline at end of file