use property rather than getter for hero party

Assets/Prefabs/Hero.prefab

@@ -50,7 +50,7 @@ MonoBehaviour:
   level: 0
   xp: 0
   attrs: {fileID: 0}
-  party: {fileID: 11400000, guid: c9a46588e6ec04d4d91bb80fdffd7869, type: 2}
+  _party: {fileID: 11400000, guid: c9a46588e6ec04d4d91bb80fdffd7869, type: 2}
 --- !u!1 &4632618406133265053
 GameObject:
   m_ObjectHideFlags: 0

Assets/Scripts/HeroUnit.cs

@@ -1,6 +1,7 @@
 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
+using UnityEngine.Assertions;
 
 using System.Runtime.CompilerServices;
 [assembly: InternalsVisibleTo("TestsPlaymode")]
@@ -16,21 +17,17 @@ public class HeroUnit : MonoBehaviour
     [SerializeField] private long level;
     [SerializeField] private long xp;
     [SerializeField] private HeroAttributesSO attrs;
-    [SerializeField] private HeroPartySO party;
+    [SerializeField] private HeroPartySO _party;
+    internal HeroPartySO party => _party;
 
     private void OnEnable()
     {
-        // NOTE(zeph): Party is mandatory. If none is set, we want an exception.
-        party.Add(this);
+        Assert.IsNotNull(_party);
+        _party.Add(this);
     }
 
     private void OnDisable()
     {
-        party.Remove(this);
-    }
-
-    internal HeroPartySO getParty()
-    {
-        return party;
+        _party.Remove(this);
     }
 }

Assets/TestsPlaymode/HeroPartyTest.cs

@@ -14,11 +14,10 @@ public IEnumerator HeroPartyGetsAllTheHeroes()
         Assert.IsNotNull(prefab);
         var instance = Object.Instantiate(prefab);
         var hero = instance.GetComponent<HeroUnit>();
-        var party = hero.getParty();
         yield return null;
-        Assert.AreEqual(1, party.Count);
+        Assert.AreEqual(1, hero.party.Count);
         Object.Destroy(instance);
         yield return null;
-        Assert.IsEmpty(party.UnitList);
+        Assert.IsEmpty(hero.party.UnitList);
     }
 }