### Question:
TuneService { public List<Tune> getByArtist(String artist) { Preconditions.checkNotNull(!Strings.isNullOrEmpty(artist), "Artist value is required for data retrieval"); log.debug("Get by artist {}", artist); return tunesRepository.getByArtist(artist); }  List<Tune> getByGenre(String genre); List<Tune> getByArtist(String artist); List<Tune> getAll(); void store(Tune tune); void remove(Tune tune);  }### Answer:
@Test public void getByArtist() { List<Tune> byArtist = tuneService.getByArtist("Artist"); Assertions.assertThat(byArtist).hasSize(1); Mockito.verify(tunesRepository).getByArtist("Artist"); }