### Question:
Utils { public static Set<String> splitScope(final String scope) { return stringToSet(scope); }  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 shouldSplitScopeWhenScopeIsNull() { assertEquals(Utils.splitScope(null), Collections.emptySet()); }
@Test public void shouldSplitScopeWhenScopeIsEmpty() { assertEquals(Utils.splitScope(""), Collections.emptySet()); }
@Test public void shouldSplitScope() { Set<String> expectedScope = new HashSet<String>(); expectedScope.add("a"); expectedScope.add("b"); expectedScope.add("c"); assertEquals(Utils.splitScope("a b c"), expectedScope); }