UTY-2533: add commands tests for subscription (#1448)

This commit adds a couple of tests for the subscription system when sending commands.

Author: BryanJY-Wong

workers/unity/Assets/Tests/EditmodeTests/Correctness/Subscriptions/CommandTests.cs

@@ -40,6 +40,35 @@ public void SubscriptionSystem_invokes_callback_on_receiving_response()
                 });
         }
 
+        [Test]
+        public void SubscriptionSystem_does_not_invoke_callback_when_gameobject_is_unlinked()
+        {
+            World.Step(world =>
+                {
+                    world.Connection.CreateEntity(EntityId, GetTemplate());
+                })
+                .Step(world =>
+                {
+                    return world.CreateGameObject<CommandStub>(EntityId).Item2;
+                })
+                .Step((world, mono) =>
+                {
+                    mono.Sender.SendTestCommand(GetRequest(), response => throw new AssertionException("Don't call"));
+                })
+                .Step((world, mono) =>
+                {
+                    world.Linker.UnlinkGameObjectFromEntity(new EntityId(EntityId), mono.gameObject);
+                })
+                .Step(world =>
+                {
+                    world.Connection.GenerateResponses<TestCommands.Test.Request, TestCommands.Test.ReceivedResponse>(ResponseGenerator);
+                })
+                .Step((world, mono) =>
+                {
+                    Assert.IsFalse(mono.enabled);
+                });
+        }
+
         private static TestCommands.Test.ReceivedResponse ResponseGenerator(CommandRequestId id, TestCommands.Test.Request request)
         {
             return new TestCommands.Test.ReceivedResponse(
@@ -57,8 +86,8 @@ private static TestCommands.Test.ReceivedResponse ResponseGenerator(CommandReque
         private static EntityTemplate GetTemplate()
         {
             var template = new EntityTemplate();
-            template.AddComponent(new Position.Snapshot(), "worker");
-            template.AddComponent(new TestCommands.Snapshot(), "worker");
+            template.AddComponent(new Position.Snapshot());
+            template.AddComponent(new TestCommands.Snapshot());
             return template;
         }