@Test
public void writeParentKeys_noParentKey() {

    // Given
    KeyDto keyDto = mock(KeyDto.class);
    given(keyDto.getParentKey()).willReturn(null);
    given(keyDto.getKind()).willReturn("some_kind");
    given(keyDto.getId()).willReturn(1L);
    // When
    String prettifiedKey = keyPrettifier.prettifyKey(keyDto);
    // Then
    assertEquals("some_kind (1)", prettifiedKey);
}