def "inputs of a rule from an inner source are not realised if the rule is not required"() {
        given:
        def mmType = ModelTypes.modelMap(Bean)
        def events = []
        registry
            .registerInstance("input", "input") { events << "input created" }
            .registerModelMap("beans", Bean) { it.registerFactory(Bean) { new Bean(name: it) } }
            .mutate {
                it.path "beans" type mmType action { c ->

        return modelRegistry.node(ModelPath.path(path));
    }

    public static <C> ModelRegistry registerInstance(ModelRegistry modelRegistry, String path, final C c) {
        return modelRegistry.register(unmanaged(registration(ModelPath.path(path)), c));
    }

    public static <C> ModelRegistry registerInstance(ModelRegistry modelRegistry, String path, final C c, Action<? super C> action) {