Adding unit tests

Controllers/PlayerController.cs

@@ -154,6 +154,9 @@ public class PlayerController : ControllerBase
         if (currentLocation == null)
             return BadRequest("Current location not found.");
 
+        if (string.IsNullOrWhiteSpace(req.Direction))
+            return BadRequest("Direction is required.");
+
         var direction = req.Direction.ToUpper();
         var directionMap = new Dictionary<string, (int dx, int dy, string reverse)>
         {
@@ -189,16 +192,14 @@ public class PlayerController : ControllerBase
             // Generate new location
             var newX = currentLocation.X + dx;
             var newY = currentLocation.Y + dy;
-            var random = new Random();
-            var newZ = currentLocation.Z + random.Next(-1, 2); // -1, 0, or +1
+            var newZ = currentLocation.Z + Random.Shared.Next(-1, 2); // -1, 0, or +1
 
             string itemId = null;
             var spawnables = await _spawnableService.GetAllAsync();
 
             if (spawnables.Any())
             {
-                var rng = new Random();
-                var roll = rng.Next(0, 100); // 0–99
+                var roll = Random.Shared.Next(0, 100); // 0–99
 
                 foreach (var s in spawnables.OrderBy(s => s.SpawnRate))
                 {