public static Collection<ExternalResource> getExternalResourcesCollection(
            Configuration config) {
        return getExternalResourceAmountMap(config).entrySet().stream()
                .map(entry -> new ExternalResource(entry.getKey(), entry.getValue()))
                .collect(Collectors.toList());
    }
@Test
    public void testRecognizeEmptyResourceList() {
        final Configuration config = new Configuration();
        config.setString(
                ExternalResourceOptions.EXTERNAL_RESOURCE_LIST.key(), ExternalResourceOptions.NONE);
        config.setLong(
                ExternalResourceOptions.getAmountConfigOptionForResource(RESOURCE_NAME_1),
                RESOURCE_AMOUNT_1);

        final Collection<ExternalResource> externalResources =
                ExternalResourceUtils.getExternalResourcesCollection(config);

        assertThat(externalResources, is(empty()));
    }