static String[] toConfigModelsPluginDir(String configModelsPluginDirString) {
        return multiValueParameterStream(configModelsPluginDirString).toArray(String[]::new);
    }
@Test
    public void string_arrays_are_split_on_comma() {
        String[] parsed = toConfigModelsPluginDir("/home/vespa/foo,/home/vespa/bar,");
        assertEquals(2, parsed.length);
    }