Adding tests for new edit mode checks. Changing exception type.

com.unity.perception/Runtime/GroundTruth/SimulationState.cs

         {
             if (!Application.isPlaying)
             {
-                throw new NotSupportedException("Dataset generation is only supported in play mode.");
+                throw new InvalidOperationException("Dataset generation is only supported in play mode.");
             }
         }
 

com.unity.perception/Tests/Editor/SimulationManagerEditorTests.cs

+using System;
+using NUnit.Framework;
+using UnityEngine.Perception.GroundTruth;
+
+namespace GroundTruth
+{
+    public class SimulationManagerEditorTests
+    {
+        [Test]
+        public void RegisterEgo_InEditMode_Throws()
+        {
+            Assert.Throws<InvalidOperationException>(() => SimulationManager.RegisterEgo(""));
+        }
+        [Test]
+        public void RegisterAnnotationDefinition_InEditMode_Throws()
+        {
+            Assert.Throws<InvalidOperationException>(() => SimulationManager.RegisterAnnotationDefinition(""));
+        }
+        [Test]
+        public void RegisterMetricDefinition_InEditMode_Throws()
+        {
+            Assert.Throws<InvalidOperationException>(() => SimulationManager.RegisterMetricDefinition(""));
+        }
+    }
+}

com.unity.perception/Tests/Editor/SimulationManagerEditorTests.cs.meta

+fileFormatVersion: 2
+guid: d5f343d2138c4cba865d1094f6b80bff
+timeCreated: 1589923850