### Question:
AuthzHelper { public static String retrieveResourceDomain(String resource, String op, String trustDomain) { String domainName; if (ASSUME_ROLE.equalsIgnoreCase(op) && trustDomain != null) { domainName = trustDomain; } else { domainName = extractResourceDomainName(resource); } return domainName; }  static void removeRoleMembers(List<RoleMember> originalRoleMembers, List<RoleMember> removeRoleMembers); static void removeGroupMembers(List<GroupMember> originalGroupMembers, List<GroupMember> removeGroupMembers); static boolean isMemberDisabled(Integer systemDisabled); static boolean isMemberExpired(Timestamp expiration, long currentTime); static boolean shouldSkipGroupMember(GroupMember member, long currentTime); static boolean isMemberOfGroup(List<GroupMember> groupMembers, final String member); static boolean checkGroupMemberValidity(List<GroupMember> groupMembers, final String member); static boolean memberNameMatch(final String memberName, final  String matchName); static boolean shouldRunDelegatedTrustCheck(final String trust, final String trustDomain); static String retrieveResourceDomain(String resource, String op, String trustDomain); static String extractResourceDomainName(final String resource); static boolean authorityAuthorizationAllowed(Principal principal); static boolean checkRoleMemberValidity(List<RoleMember> roleMembers, final String member,
                                                  GroupMembersFetcher groupMembersFetcher); static boolean isMemberOfRole(Role role, final String member, GroupMembersFetcher groupMembersFetcher); static boolean assumeRoleResourceMatch(String roleName, Assertion assertion); static boolean matchDelegatedTrustPolicy(Policy policy, final String roleName, final String roleMember,
                                                    List<Role> roles, GroupMembersFetcher groupMembersFetcher); static boolean matchDelegatedTrustAssertion(Assertion assertion, final String roleName, final String roleMember,
                                                       List<Role> roles, GroupMembersFetcher groupMembersFetcher);  }### Answer:
@Test public void testRetrieveResourceDomainA() { assertEquals("trustdomain", AuthzHelper.retrieveResourceDomain("resource", "assume_role", "trustdomain")); assertEquals("domain1", AuthzHelper.retrieveResourceDomain("domain1:resource", "assume_role", null)); assertEquals("domain1", AuthzHelper.retrieveResourceDomain("domain1:resource", "read", null)); assertEquals("domain1", AuthzHelper.retrieveResourceDomain("domain1:resource", "read", "trustdomain")); assertEquals("domain1", AuthzHelper.retrieveResourceDomain("domain1:a:b:c:d:e", "read", "trustdomain")); assertNull(AuthzHelper.retrieveResourceDomain("domain1-invalid", "read", null)); }