public async void Intiialise_Sends_CustomMessageTypes_To_SubscriptionBuilder()
        {
            var customMessageTypeMap =
                new CustomMessageTypeMap("TestType", typeof(FakeMessage), typeof(FakeHandler));

            var customMessageTypeMaps = new[] { customMessageTypeMap };
            var assemblies            = new[] { Assembly.GetCallingAssembly() };

            await _subscriber.Initialise(assemblies, customMessageTypeMaps);

            await _subscriptionBuilder.Received(1).Build(Arg.Is <string[]>(s => s.Single() == customMessageTypeMap.MessageType), Arg.Any <string>());
        }
        public async void Intiialise_Configures_CustomMessageTypes_In_MessageMapper()
        {
            var customMessageTypeMap =
                new CustomMessageTypeMap("TestType", typeof(FakeMessage), typeof(FakeHandler));

            var customMessageTypeMaps = new[] { customMessageTypeMap };
            var assemblies            = new[] { Assembly.GetCallingAssembly() };


            await _subscriber.Initialise(assemblies, customMessageTypeMaps);

            var actual = MessageMapper.GetHandlerForMessageType(customMessageTypeMap.MessageType);

            Assert.Equal(customMessageTypeMap.MappedMessageType, actual.MessageType);
            Assert.Equal(customMessageTypeMap.HandlerType, actual.HandlerType);
        }