feat: add first loose condition

src/game.zig

@@ -73,6 +73,12 @@ const Game = struct {
         }
 
         const newHead = self.body.items[0] + self.direction.vector();
+        if (newHead[0] == 0 or newHead[0] == self.playFieldSize[0] or
+            newHead[1] == 0 or newHead[1] == self.playFieldSize[1])
+        {
+            self.state = State.lost;
+            return;
+        }
         try self.body.insert(0, newHead);
         _ = self.body.pop();
     }
@@ -116,7 +122,22 @@ test "should not be able to change direction to the previous position" {
     try testing.expectEqual(Direction.right, game.direction);
 }
 
-test "should loose if exiting playField" {}
+test "should loose if exiting playField right" {
+    const allocator = testing.allocator;
+
+    var game = try Game.create(allocator);
+    defer game.deinit();
+
+    for (0..10) |_| {
+        try game.tick();
+    }
+
+    const expected = [_]Vec2{ Vec2{ 19, 10 }, Vec2{ 18, 10 }, Vec2{ 17, 10 } };
+    try testing.expectEqualSlices(Vec2, &expected, game.body.items);
+
+    try testing.expectEqual(State.lost, game.state);
+}
+
 test "should loose if eating itself" {}
 test "should grow if eating food" {}
 test "should win if no space is left" {}