/**
   * purgeRelationship should be idempotent with respect to the returned HTTP status code. The
   * response body however, should indicate "false" for successive deletes of the same resource.
   *
   * @throws Exception
   */
  @Test
  public void testIdempotency() throws Exception {
    FedoraResponse response = null;
    Model model = null;
    Statement s = null;
    String subject = String.format("info:fedora/%s", testPid);
    String predicate = "urn:foo/p";
    String object = "你好";

    // first add a relationship
    response = addRelationship(testPid).predicate(predicate).object(object, true).execute();
    assertEquals(200, response.getStatus());

    // verify it was added
    response = getRelationships(testPid).predicate(predicate).execute();
    assertEquals(200, response.getStatus());
    model = ModelFactory.createDefaultModel();
    model.read(response.getEntityInputStream(), null, FileUtils.langXML);
    StmtIterator it = model.listStatements();
    while (it.hasNext()) {
      s = it.next();
      assertEquals(subject, s.getSubject().toString());
      assertEquals(predicate, s.getPredicate().toString());
      assertEquals(object, s.getObject().toString());
    }

    // now delete it
    response = purgeRelationship(testPid).predicate(predicate).object(object, true).execute();
    assertEquals(200, response.getStatus());
    assertEquals("true", response.getEntity(String.class));

    // verify it's gone
    response = getRelationships(testPid).predicate(predicate).execute();
    assertEquals(200, response.getStatus());
    model = ModelFactory.createDefaultModel();
    model.read(response.getEntityInputStream(), null, FileUtils.langXML);
    it = model.listStatements();
    while (it.hasNext()) {
      s = it.next();
      assertFalse(predicate.equals(s.getPredicate().toString()));
      assertFalse(object.equals(s.getObject().toString()));
    }

    response = purgeRelationship(testPid).predicate(predicate).object(object, true).execute();
    assertEquals(200, response.getStatus());
    assertEquals("false", response.getEntity(String.class));
  }
 protected void naiveGetDatastreams(Set<String> pids, Set<String> dsids) throws Exception {
   FedoraResponse response = null;
   for (String pid : pids) {
     for (String dsid : dsids) {
       response = getDatastreamDissemination(pid, dsid).execute();
       assertEquals(200, response.getStatus());
       response.getEntity(String.class);
       response.close();
     }
   }
 }