@PublicAPI(usage = ACCESS)
    public Properties getExtensionProperties(String extensionIdentifier) {
        String propertyPrefix = getFullExtensionPropertyPrefix(extensionIdentifier);
        return getSubProperties(propertyPrefix);
    }
@Test
    public void if_no_extension_properties_are_found_empty_properties_are_returned() {
        ArchConfiguration configuration = testConfiguration(PROPERTIES_FILE_NAME);

        assertThat(configuration.getExtensionProperties("not-there")).isEmpty();
    }