### Question:
GroupMembershipChangeUpdate extends Update { @Override public void applyUpdate(RepositorySet repositorySet) { GroupMembership membership = new GroupMembership (membershipDescription.accountID, membershipDescription .groupID); membership.setSharingUntil(membershipDescription.sharingUntil); repositorySet.userGroupRepository.updateMembership(membership); } GroupMembershipChangeUpdate(@JsonProperty("time-created")
                                               Date timeCreated,
                                       @JsonProperty("creator") int creator,
                                       @JsonProperty("membership")
                                               CompleteMembership
                                               membershipDescription); @Override void applyUpdate(RepositorySet repositorySet);  }### Answer:
@Test public void applyUpdate() throws Exception { GroupMembershipChangeUpdate update = new GroupMembershipChangeUpdate(date, creator1, membership); update.applyUpdate(mockRepos); verify(mockGroupMembership).setSharingUntil(date); verify(mockUserGroupRepository).updateMembership(mockGroupMembership); }