test: add EditMode test assembly

Assets/Tests/EditMode/DecayGrid.Tests.EditMode.asmdef

@@ -0,0 +1,21 @@
+{
+    "name": "DecayGrid.Tests.EditMode",
+    "rootNamespace": "DecayGrid.Tests",
+    "references": [
+        "UnityEngine.TestRunner",
+        "UnityEditor.TestRunner"
+    ],
+    "includePlatforms": [
+        "Editor"
+    ],
+    "excludePlatforms": [],
+    "allowUnsafeCode": false,
+    "overrideReferences": true,
+    "precompiledReferences": [
+        "nunit.framework.dll"
+    ],
+    "autoReferenced": false,
+    "defineConstraints": [],
+    "versionDefines": [],
+    "noEngineReferences": false
+}

Assets/Tests/EditMode/StatusManagerTests.cs

@@ -0,0 +1,18 @@
+using NUnit.Framework;
+using Core.Domain.Status;
+
+namespace DecayGrid.Tests
+{
+    public class StatusManagerTests
+    {
+        [Test]
+        public void DefaultCapabilities_HaveExpectedValues()
+        {
+            var sm = new StatusManager();
+            var caps = sm.CurrentCapabilities;
+            Assert.IsTrue(caps.CanTriggerDecay);
+            Assert.AreEqual(1f, caps.SpeedMultiplier, 0.001f);
+            Assert.IsFalse(caps.CanHover);
+        }
+    }
+}