public <T> List<Class<? extends T>> scanForSubClassesInPackage(String packageName, Class<T> parentClass) {
        return scanForClassesInPackage(packageName, isSubClassOf(parentClass))
                .stream()
                .map(aClass -> (Class<? extends T>) aClass.asSubclass(parentClass))
                .collect(toList());
    }
@Test
    void scanForSubClassesInNonExistingPackage() {
        List<Class<? extends ExampleInterface>> classes = scanner
                .scanForSubClassesInPackage("io.cucumber.core.resource.does.not.exist", ExampleInterface.class);
        assertThat(classes, empty());
    }