@Test
public void shouldReturnEmptyStringWhenNullLevelValueAndNoTypeRegistered() {

    // given
    Parameter metadata = new SimpleParameter().withLevel(new SimpleLevel().withName("null"));
    MapEntry map = new MapEntry().put("null", null);
    // when
    ParameterEntry entry = converter.asEntry(metadata, map);
    // then
    assertThat(entry).hasLevels("");
}