### Question:
Utils { public static boolean isEmpty(final String s) { return s == null || s.isEmpty(); }  static boolean isEmpty(final String s); static boolean isEmpty(final Collection<?> c); static boolean isEmpty(final Map<?, ?> m); static Set<String> splitResponseType(final String responseType); static Set<String> splitScope(final String scope); static String joinScope(final Set<String> scope); static Set<String> stringToSet(String string); static boolean isOpenIdConnectFragmentErrorType(Set<String> requestedResponseTypes); static boolean isOAuth2FragmentErrorType(Set<String> requestedResponseTypes); static boolean isOpenIdConnectClient(ClientRegistration clientRegistration); static UrlLocation getRequiredUrlLocation(OAuth2Request request, ClientRegistration clientRegistration); static UrlLocation getRequiredUrlLocation(Set<String> responseTypes, ClientRegistration clientRegistration); static List<T> asSortedList(Collection<T> collection,
                                                                         Comparator<? super T> comp);  }### Answer:
@Test public void isEmptyShouldReturnTrueWhenStringIsNull() { assertTrue(Utils.isEmpty((String) null)); }
@Test public void isEmptyShouldReturnTrueWhenStringIsEmpty() { assertTrue(Utils.isEmpty("")); }
@Test public void isEmptyShouldReturnFalseWhenStringIsNotEmpty() { assertFalse(Utils.isEmpty("WHATEVER")); }
@Test public void isEmptyShouldReturnTrueWhenCollectionIsNull() { assertTrue(Utils.isEmpty((Collection<?>) null)); }
@Test public void isEmptyShouldReturnTrueWhenCollectionIsEmpty() { assertTrue(Utils.isEmpty(Collections.emptyList())); }
@Test public void isEmptyShouldReturnFalseWhenCollectionIsNotEmpty() { assertFalse(Utils.isEmpty(Collections.singleton("WHATEVER"))); }
@Test public void isEmptyShouldReturnTrueWhenMapIsNull() { assertTrue(Utils.isEmpty((Map<?, ?>) null)); }
@Test public void isEmptyShouldReturnTrueWhenMapIsEmpty() { assertTrue(Utils.isEmpty(Collections.emptyMap())); }
@Test public void isEmptyShouldReturnFalseWhenMapIsNotEmpty() { assertFalse(Utils.isEmpty(Collections.singletonMap("WHAT", "EVER"))); }