diff --git a/tests/integrated/command-fixture.cpp b/tests/integrated/command-fixture.cpp
new file mode 100644
index 0000000..be800e2
--- /dev/null
+++ b/tests/integrated/command-fixture.cpp
@@ -0,0 +1,34 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014-2017, Regents of the University of California.
+ *
+ * This file is part of NDN repo-ng (Next generation of NDN repository).
+ * See AUTHORS.md for complete list of repo-ng authors and contributors.
+ *
+ * repo-ng is free software: you can redistribute it and/or modify it under the terms
+ * of the GNU General Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later version.
+ *
+ * repo-ng is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+ * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * repo-ng, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "command-fixture.hpp"
+
+namespace repo {
+namespace tests {
+
+CommandFixture::CommandFixture()
+  : scheduler(repoFace.getIoService())
+  , keyChain(m_keyChain)
+{
+  this->saveIdentityCertificate(keyChain.getPib().getDefaultIdentity().getName(),
+                                "tests/integrated/insert-delete-test.cert");
+}
+
+} // namespace tests
+} // namespace repo
diff --git a/tests/integrated/command-fixture.hpp b/tests/integrated/command-fixture.hpp
new file mode 100644
index 0000000..341e00c
--- /dev/null
+++ b/tests/integrated/command-fixture.hpp
@@ -0,0 +1,46 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014-2017, Regents of the University of California.
+ *
+ * This file is part of NDN repo-ng (Next generation of NDN repository).
+ * See AUTHORS.md for complete list of repo-ng authors and contributors.
+ *
+ * repo-ng is free software: you can redistribute it and/or modify it under the terms
+ * of the GNU General Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later version.
+ *
+ * repo-ng is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+ * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * repo-ng, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef REPO_TESTS_INTEGRATED_COMMAND_FIXTURE_HPP
+#define REPO_TESTS_INTEGRATED_COMMAND_FIXTURE_HPP
+
+#include "../identity-management-fixture.hpp"
+#include <ndn-cxx/security/validator-null.hpp>
+
+namespace repo {
+namespace tests {
+
+class CommandFixture : public virtual IdentityManagementFixture
+{
+protected:
+  CommandFixture();
+
+protected:
+  Face repoFace;
+  Scheduler scheduler;
+  KeyChain& keyChain;
+
+  /// \todo #4091 switch to ValidatorPolicyConf and load insert-delete-validator-config.conf
+  ndn::ValidatorNull validator;
+};
+
+} // namespace tests
+} // namespace repo
+
+#endif // REPO_TESTS_INTEGRATED_COMMAND_FIXTURE_HPP
diff --git a/tests/integrated/test-basic-command-insert-delete.cpp b/tests/integrated/test-basic-command-insert-delete.cpp
index f9e58e3..775a16d 100644
--- a/tests/integrated/test-basic-command-insert-delete.cpp
+++ b/tests/integrated/test-basic-command-insert-delete.cpp
@@ -21,13 +21,12 @@
 #include "handles/delete-handle.hpp"
 #include "storage/sqlite-storage.hpp"
 #include "storage/repo-storage.hpp"
-#include "common.hpp"
 
+#include "command-fixture.hpp"
 #include "../repo-storage-fixture.hpp"
 #include "../dataset-fixtures.hpp"
 
 #include <ndn-cxx/util/random.hpp>
-#include <ndn-cxx/util/io.hpp>
 #include <boost/preprocessor/comparison/not_equal.hpp>
 #include <boost/test/unit_test.hpp>
 #include <fstream>
@@ -46,13 +45,11 @@
 const static uint8_t content[8] = {3, 1, 4, 1, 5, 9, 2, 6};
 
 template<class Dataset>
-class Fixture : public RepoStorageFixture, public Dataset
+class Fixture : public CommandFixture, public RepoStorageFixture, public Dataset
 {
 public:
   Fixture()
-    : scheduler(repoFace.getIoService())
-    , validator(repoFace)
-    , writeHandle(repoFace, *handle, keyChain, scheduler, validator)
+    : writeHandle(repoFace, *handle, keyChain, scheduler, validator)
     , deleteHandle(repoFace, *handle, keyChain, scheduler, validator)
     , insertFace(repoFace.getIoService())
     , deleteFace(repoFace.getIoService())
@@ -61,14 +58,6 @@
     deleteHandle.listen(Name("/repo/command"));
   }
 
-  ~Fixture()
-  {
-    repoFace.getIoService().stop();
-  }
-
-  void
-  generateDefaultCertificateFile();
-
   void
   scheduleInsertEvent();
 
@@ -85,10 +74,6 @@
   delayedInterest();
 
   void
-  stopFaceProcess();
-
-
-  void
   onInsertData(const Interest& interest, const Data& data);
 
   void
@@ -113,10 +98,6 @@
   checkDeleteOk(const Interest& interest);
 
 public:
-  Face repoFace;
-  Scheduler scheduler;
-  ValidatorConfig validator;
-  KeyChain keyChain;
   WriteHandle writeHandle;
   DeleteHandle deleteHandle;
   Face insertFace;
@@ -124,29 +105,13 @@
   std::map<Name, EventId> insertEvents;
 };
 
-template<class T>  void
-Fixture<T>::generateDefaultCertificateFile()
-{
-  Name defaultIdentity = keyChain.getDefaultIdentity();
-  Name defaultKeyname = keyChain.getDefaultKeyNameForIdentity(defaultIdentity);
-  Name defaultCertficateName = keyChain.getDefaultCertificateNameForKey(defaultKeyname);
-  shared_ptr<ndn::IdentityCertificate> defaultCertficate =
-    keyChain.getCertificate(defaultCertficateName);
-  //test-integrated should run in root directory of repo-ng.
-  //certificate file should be removed after tests for security issue.
-  std::fstream certificateFile("tests/integrated/insert-delete-test.cert",
-                               std::ios::out | std::ios::binary | std::ios::trunc);
-  ndn::io::save(*defaultCertficate, certificateFile);
-  certificateFile.close();
-}
-
 template<class T> void
 Fixture<T>::onInsertInterest(const Interest& interest)
 {
   Data data(Name(interest.getName()));
   data.setContent(content, sizeof(content));
   data.setFreshnessPeriod(milliseconds(0));
-  keyChain.signByIdentity(data, keyChain.getDefaultIdentity());
+  keyChain.sign(data);
   insertFace.put(data);
   std::map<Name, EventId>::iterator event = insertEvents.find(interest.getName());
   if (event != insertEvents.end()) {
@@ -173,12 +138,6 @@
 }
 
 template<class T> void
-Fixture<T>::stopFaceProcess()
-{
-  repoFace.getIoService().stop();
-}
-
-template<class T> void
 Fixture<T>::onInsertData(const Interest& interest, const Data& data)
 {
   RepoCommandResponse response;
@@ -265,7 +224,7 @@
 
     insertCommandName.append(insertParameter.wireEncode());
     Interest insertInterest(insertCommandName);
-    keyChain.signByIdentity(insertInterest, keyChain.getDefaultIdentity());
+    keyChain.sign(insertInterest);
     //schedule a job to express insertInterest every 50ms
     scheduler.scheduleEvent(milliseconds(timeCount * 50 + 1000),
                             bind(&Fixture<T>::sendInsertInterest, this, insertInterest));
@@ -298,7 +257,7 @@
     deleteParameter.setName((*i)->getName());
     deleteCommandName.append(deleteParameter.wireEncode());
     Interest deleteInterest(deleteCommandName);
-    keyChain.signByIdentity(deleteInterest, keyChain.getDefaultIdentity());
+    keyChain.sign(deleteInterest);
     scheduler.scheduleEvent(milliseconds(4000 + timeCount * 50),
                             bind(&Fixture<T>::sendDeleteInterest, this, deleteInterest));
     timeCount++;
@@ -313,19 +272,13 @@
 
 BOOST_FIXTURE_TEST_CASE_TEMPLATE(InsertDelete, T, Datasets, Fixture<T>)
 {
-  this->generateDefaultCertificateFile();
-  this->validator.load("tests/integrated/insert-delete-validator-config.conf");
-
   // schedule events
   this->scheduler.scheduleEvent(seconds(0),
                                 bind(&Fixture<T>::scheduleInsertEvent, this));
   this->scheduler.scheduleEvent(seconds(10),
                                 bind(&Fixture<T>::scheduleDeleteEvent, this));
 
-  // schedule an event to terminate IO
-  this->scheduler.scheduleEvent(seconds(30),
-                                bind(&Fixture<T>::stopFaceProcess, this));
-  this->repoFace.getIoService().run();
+  this->repoFace.processEvents(seconds(30));
 }
 
 BOOST_AUTO_TEST_SUITE_END()
diff --git a/tests/integrated/test-basic-command-watch.cpp b/tests/integrated/test-basic-command-watch.cpp
index 8c4c13e..8b8f327 100644
--- a/tests/integrated/test-basic-command-watch.cpp
+++ b/tests/integrated/test-basic-command-watch.cpp
@@ -19,13 +19,12 @@
 
 #include "handles/watch-handle.hpp"
 #include "storage/sqlite-storage.hpp"
-#include "common.hpp"
 
+#include "command-fixture.hpp"
 #include "../repo-storage-fixture.hpp"
 #include "../dataset-fixtures.hpp"
 
 #include <ndn-cxx/util/random.hpp>
-#include <ndn-cxx/util/io.hpp>
 
 #include <boost/test/unit_test.hpp>
 #include <fstream>
@@ -44,26 +43,16 @@
 const static uint8_t content[8] = {3, 1, 4, 1, 5, 9, 2, 6};
 
 template<class Dataset>
-class Fixture : public RepoStorageFixture, public Dataset
+class Fixture : public CommandFixture, public RepoStorageFixture, public Dataset
 {
 public:
   Fixture()
-    : scheduler(repoFace.getIoService())
-    , validator(repoFace)
-    , watchHandle(repoFace, *handle, keyChain, scheduler, validator)
+    : watchHandle(repoFace, *handle, keyChain, scheduler, validator)
     , watchFace(repoFace.getIoService())
   {
     watchHandle.listen(Name("/repo/command"));
   }
 
-  ~Fixture()
-  {
-    repoFace.getIoService().stop();
-  }
-
-  void
-  generateDefaultCertificateFile();
-
   void
   scheduleWatchEvent();
 
@@ -77,9 +66,6 @@
   delayedInterest();
 
   void
-  stopFaceProcess();
-
-  void
   onWatchData(const Interest& interest, const Data& data);
 
   void
@@ -98,38 +84,18 @@
   checkWatchOk(const Interest& interest);
 
 public:
-  Face repoFace;
-  Scheduler scheduler;
-  ValidatorConfig validator;
-  KeyChain keyChain;
   WatchHandle watchHandle;
   Face watchFace;
   std::map<Name, EventId> watchEvents;
 };
 
-template<class T>  void
-Fixture<T>::generateDefaultCertificateFile()
-{
-  Name defaultIdentity = keyChain.getDefaultIdentity();
-  Name defaultKeyname = keyChain.getDefaultKeyNameForIdentity(defaultIdentity);
-  Name defaultCertficateName = keyChain.getDefaultCertificateNameForKey(defaultKeyname);
-  shared_ptr<ndn::IdentityCertificate> defaultCertficate =
-  keyChain.getCertificate(defaultCertficateName);
-  //test-integrated should run in root directory of repo-ng.
-  //certificate file should be removed after tests for security issue.
-  std::fstream certificateFile("tests/integrated/insert-delete-test.cert",
-                               std::ios::out | std::ios::binary | std::ios::trunc);
-  ndn::io::save(*defaultCertficate, certificateFile);
-  certificateFile.close();
-}
-
 template<class T> void
 Fixture<T>::onWatchInterest(const Interest& interest)
 {
   shared_ptr<Data> data = make_shared<Data>(Name(interest.getName()).appendNumber(random::generateWord64()+100));
   data->setContent(content, sizeof(content));
   data->setFreshnessPeriod(milliseconds(0));
-  keyChain.signByIdentity(*data, keyChain.getDefaultIdentity());
+  keyChain.sign(*data);
   watchFace.put(*data);
 
   // schedule an event 50ms later to check whether watch is Ok
@@ -152,12 +118,6 @@
 }
 
 template<class T> void
-Fixture<T>::stopFaceProcess()
-{
-  repoFace.getIoService().stop();
-}
-
-template<class T> void
 Fixture<T>::onWatchData(const Interest& interest, const Data& data)
 {
   RepoCommandResponse response;
@@ -226,7 +186,7 @@
   watchParameter.setWatchTimeout(milliseconds(1000000000));
   watchCommandName.append(watchParameter.wireEncode());
   Interest watchInterest(watchCommandName);
-  keyChain.signByIdentity(watchInterest, keyChain.getDefaultIdentity());
+  keyChain.sign(watchInterest);
   //schedule a job to express watchInterest
   scheduler.scheduleEvent(milliseconds(1000),
                           bind(&Fixture<T>::sendWatchStartInterest, this, watchInterest));
@@ -235,7 +195,7 @@
   RepoCommandParameter watchStopParameter;
   watchStopName.append(watchStopParameter.wireEncode());
   Interest watchStopInterest(watchStopName);
-  keyChain.signByIdentity(watchStopInterest, keyChain.getDefaultIdentity());
+  keyChain.sign(watchStopInterest);
 
  // scheduler.scheduleEvent(milliseconds(10000),
   //                        bind(&Fixture<T>::sendWatchStopInterest, this, watchStopInterest));
@@ -250,17 +210,11 @@
 
 BOOST_FIXTURE_TEST_CASE_TEMPLATE(WatchDelete, T, Dataset, Fixture<T>)
 {
-  this->generateDefaultCertificateFile();
-  this->validator.load("tests/integrated/insert-delete-validator-config.conf");
-
   // schedule events
   this->scheduler.scheduleEvent(seconds(0),
                                 bind(&Fixture<T>::scheduleWatchEvent, this));
 
-  // schedule an event to terminate IO
-  this->scheduler.scheduleEvent(seconds(500),
-                                bind(&Fixture<T>::stopFaceProcess, this));
-  this->repoFace.getIoService().run();
+  this->repoFace.processEvents(seconds(500));
 }
 
 BOOST_AUTO_TEST_SUITE_END()
diff --git a/tests/integrated/test-basic-interest-read.cpp b/tests/integrated/test-basic-interest-read.cpp
index 79a7e8f..eb412e8 100644
--- a/tests/integrated/test-basic-interest-read.cpp
+++ b/tests/integrated/test-basic-interest-read.cpp
@@ -81,12 +81,6 @@
   }
 
   void
-  stopFaceProcess()
-  {
-    repoFace.getIoService().stop();
-  }
-
-  void
   onReadData(const ndn::Interest& interest, const ndn::Data& data)
   {
     int rc = memcmp(data.getContent().value(), content, sizeof(content));
@@ -137,10 +131,7 @@
   this->scheduler.scheduleEvent(ndn::time::seconds(0),
                                 bind(&BasicInterestReadFixture<T>::scheduleReadEvent, this));
 
-  // schedule an event to terminate IO
-  this->scheduler.scheduleEvent(ndn::time::seconds(20),
-                                bind(&BasicInterestReadFixture<T>::stopFaceProcess, this));
-  this->repoFace.getIoService().run();
+  this->repoFace.processEvents(ndn::time::seconds(20));
 
 }