CountryServiceImpl implements CountryService { @Override public Map<String, String> getAllCountries() { return countries; } CountryServiceImpl(); @Override String getCountryByIsoCode(String isoCode); @Override Map<String, String> getAllCountries();  }
@Test public void testGetAllCountries() { Map<String,String> countries = countryService.getAllCountries(); assertNotNull(countries); assertEquals(4, countries.size()); assertEquals("Canada", countries.get("CA")); assertEquals("Germany", countries.get("DE")); }