Unit testing Application Bootstrapper class of Nancy based API

We have an API built on Nancy Framework, and it has a bootstrapper class which is like a AppStart class, and has the below code

protected override void ApplicationStartup(IWindsorContainer container, IPipelines pipelines) { base.ApplicationStartup(container, pipelines);

        pipelines.OnError += (ctx, e) =>
        {
            _logger.Error("Unhandled error occured.", e);
            return null;
        };
    }

How can I test this using Rhino mocks?