} catch (ClassNotFoundException) {
            // expected
        }
    }

    ClassLoader filter(Class<?> aClass) {
        def spec = new FilteringClassLoader.Spec()
        spec.allowClass(aClass)
        return new FilteringClassLoader(aClass.classLoader, spec)
    }

    ClassLoader isolated(ClassLoader parent = ClassLoader.systemClassLoader.parent, Class<?>... classes) {

        then:
        ClassNotFoundException e = thrown()
    }

    ClassLoader getGroovyClassLoader() {
        def spec = new FilteringClassLoader.Spec()
        spec.allowPackage("groovy")
        return new FilteringClassLoader(getClass().classLoader, spec)
    }

    def compileJavaToDir(String className, String text) {
        srcDir.createDir()

     *
     * @param parent the parent ClassLoader
     * @param spec the filtering spec for the classloader
     * @return The ClassLoader
     */
    ClassLoader createFilteringClassLoader(ClassLoader parent, FilteringClassLoader.Spec spec);

        when:
        def cl = new URLClassLoader(classpath.asURLArray, factory.createFilteringClassLoader(getClass().classLoader, new FilteringClassLoader.Spec()))
        def c = cl.loadClass(DefaultClassLoaderFactoryTestHelper.name)

        then:
        c != DefaultClassLoaderFactoryTestHelper

        when: