add test for singular ReadMessageWithEntity

test/EngineTest.cs

@@ -497,6 +497,58 @@ namespace Tests
             entityMessageResults.Should().BeEmpty();
         }
 
+        [Sends(typeof(EntityMessage), typeof(MockMessage))]
+        class EntityMessageSingularEmitterEngine : Engine
+        {
+            private Entity _entity;
+
+            public EntityMessageSingularEmitterEngine(Entity entity)
+            {
+                _entity = entity;
+            }
+
+            public override void Update(double dt)
+            {
+                SendMessage(new EntityMessage(_entity, 2));
+                SendMessage(new MockMessage());
+            }
+        }
+
+        static EntityMessage entityMessageResult;
+
+        [Receives(typeof(EntityMessage))]
+        class SingularMessageWithEntityEngine : Engine
+        {
+            private Entity _entity;
+
+            public SingularMessageWithEntityEngine(Entity entity)
+            {
+                _entity = entity;
+            }
+
+            public override void Update(double dt)
+            {
+                entityMessageResult = ReadMessageWithEntity<EntityMessage>(_entity);
+            }
+        }
+
+        [Test]
+        public void MessageWithEntity()
+        {
+            var worldBuilder = new WorldBuilder();
+
+            var entity = worldBuilder.CreateEntity();
+
+            worldBuilder.AddEngine(new EntityMessageSingularEmitterEngine(entity));
+            worldBuilder.AddEngine(new SingularMessageWithEntityEngine(entity));
+
+            var world = worldBuilder.Build();
+
+            world.Update(0.01);
+
+            entityMessageResult.Should().Be(new EntityMessage(entity, 2));
+        }
+
         class SomeComponentTestEngine : Engine
         {
             public override void Update(double dt)