String[] secondNames = new String[3];
secondNames[0] = "secondName1";
secondNames[1] = "secondName2";
secondNames[2] = "secondName3";
Individuals source = newInstance(Individuals.class);
source.setUsernames(userNames);
source.setSimpleField("a very simple field");
source.setSecondNames(secondNames);
Set<String> mySet = newInstance(HashSet.class);
mySet.add("myString");
source.setAddressSet(mySet);
FlatIndividual dest = mapper.map(source, FlatIndividual.class);
assertEquals(source.getUsernames().get(0), dest.getUsername1());
assertEquals(source.getSimpleField(), dest.getSimpleField());
assertEquals(source.getSecondNames()[1], dest.getSecondName1());
assertEquals(source.getSecondNames()[2], dest.getSecondName2());
assertEquals("myString", dest.getAddress());
}