CountryServiceImpl implements CountryService { @Override public String getCountryByIsoCode(String isoCode) { return countries.get(isoCode); } CountryServiceImpl(); @Override String getCountryByIsoCode(String isoCode); @Override Map<String, String> getAllCountries();  }
@Test public void testGetCountryByIsoCode() { String countryName = countryService.getCountryByIsoCode("CA"); assertEquals("Canada", countryName); }