From 9057228795a13e1bd3e1fccf92047710dd165073 Mon Sep 17 00:00:00 2001
From: Evan Hemsley <2342303+ehemsley@users.noreply.github.com>
Date: Sun, 29 Dec 2019 20:41:35 -0800
Subject: [PATCH] fix bug when no messages existed for queried entity

---
 encompass-cs/Collections/TypedMessageStore.cs |  2 +-
 test/EngineTest.cs                            | 14 ++++++++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/encompass-cs/Collections/TypedMessageStore.cs b/encompass-cs/Collections/TypedMessageStore.cs
index aef3a5c..54aebe6 100644
--- a/encompass-cs/Collections/TypedMessageStore.cs
+++ b/encompass-cs/Collections/TypedMessageStore.cs
@@ -90,7 +90,7 @@ namespace Encompass
 
         public IEnumerable<TMessage> WithEntity(int entityID)
         {
-            return entityToMessage[entityID];
+            return entityToMessage.ContainsKey(entityID) ? entityToMessage[entityID] : System.Linq.Enumerable.Empty<TMessage>();
         }
 
         public override void Clear()
diff --git a/test/EngineTest.cs b/test/EngineTest.cs
index 7e095dd..74dae7e 100644
--- a/test/EngineTest.cs
+++ b/test/EngineTest.cs
@@ -483,6 +483,20 @@ namespace Tests
             entityMessageResults.Should().ContainEquivalentOf(new EntityMessage(entity, 5));
         }
 
+        [Test]
+        public void NoMessagesWithEntity()
+        {
+            var worldBuilder = new WorldBuilder();
+
+            var entity = worldBuilder.CreateEntity();
+            worldBuilder.AddEngine(new EntityMessageReceiverEngine(entity));
+
+            var world = worldBuilder.Build();
+            world.Update(0.01);
+
+            entityMessageResults.Should().BeEmpty();
+        }
+
         class SomeComponentTestEngine : Engine
         {
             public override void Update(double dt)