public void Should_return_previously_provided_handler()
        {
            // ReSharper disable once ConvertToLocalFunction
            EventHandler <ITestAbstraction> handler = (s, args) =>
            {
            };

            var mappedHandler = _lookup.MapForAttachment(handler, impl => new TestAdapter());
            var mappedHandlerForDetachment = _lookup.TryMapForDetachment(handler);

            mappedHandler.Should().Be(mappedHandlerForDetachment);
        }
        public void Should_return_null_if_handler_is_null()
        {
            var handler = _lookup.MapForAttachment(null, implementation => new TestAdapter());

            handler.Should().BeNull();
        }