### Question:
ModelMerger { protected void mergeContributor_Roles( Contributor target, Contributor source, boolean sourceDominant, Map<Object, Object> context ) { target.setRoles( merge( target.getRoles(), source.getRoles(), sourceDominant, e -> e ) ); }  void merge( Model target, Model source, boolean sourceDominant, Map<?, ?> hints );  }### Answer:
@Test public void mergeSameRoles() { Contributor target = new Contributor(); target.setRoles( Arrays.asList( "first", "second", "third" ) ); Contributor source = new Contributor(); source.setRoles( Arrays.asList( "first", "second", "third" ) ); modelMerger.mergeContributor_Roles( target, source, true, null ); assertThat( target.getRoles(), contains( "first", "second", "third" ) ); }