### Question:
AuthorizationGrantFileDAOImpl implements AuthorizationGrantDAO { @Override public void removeGrant(UUID entityId, UUID placeId) { Map<UUID, AuthorizationGrant> placeGrants = grants.get(entityId); if(placeGrants != null) { placeGrants.remove(placeId); } } AuthorizationGrantFileDAOImpl(); @Override void save(AuthorizationGrant grant); @Override List<AuthorizationGrant> findForEntity(UUID entityId); @Override List<AuthorizationGrant> findForPlace(UUID placeId); @Override void removeForPlace(UUID placeId); @Override void removeGrantsForEntity(UUID entityId); @Override void removeGrant(UUID entityId, UUID placeId);  }### Answer:
@Test public void testRemoveGrant() { List<AuthorizationGrant> grants = fileDao.findForEntity(entityId); assertNotNull(grants); assertEquals(1, grants.size()); fileDao.removeGrant(entityId, UUID.fromString("6f293fd5-b65b-4a63-a5ed-1309eda1122a")); grants = fileDao.findForEntity(entityId); assertNotNull(grants); assertEquals(0, grants.size()); }