expect:
        detector.getDeclaredSources(SourcesNotDeclaredAlphabetically).toList() == [SourcesNotDeclaredAlphabetically.A, SourcesNotDeclaredAlphabetically.B]
    }

    private void addClass(GroovyClassLoader cl, String impl) {
        def type = cl.parseClass(impl)
        detector.getDeclaredSources(type)
        type = null
    }

                }
            });

    // TODO return a richer data structure that provides meta data about how the source was found, for use is diagnostics
    public Iterable<Class<? extends RuleSource>> getDeclaredSources(Class<?> container) {
        try {
            return FluentIterable.from(cache.get(container))
                    .transform(new Function<Reference<Class<? extends RuleSource>>, Class<? extends RuleSource>>() {

        target.prepareForRuleBasedPlugins();
        ModelRegistry modelRegistry = target.getModelRegistry();
        Iterable<Class<? extends RuleSource>> declaredSources = ruleDetector.getDeclaredSources(clazz);
        for (Class<? extends RuleSource> ruleSource : declaredSources) {
            ExtractedRuleSource<?> rules = ruleInspector.extract(ruleSource);
            for (Class<?> dependency : rules.getRequiredPlugins()) {