Avoid deprecated Boost.Asio interfaces

Change-Id: I00d285893ff61619f49dff8a8a55d0d0e2c309a7
diff --git a/tests/integration/face.cpp b/tests/integration/face.cpp
index 7bd2408..a759e35 100644
--- a/tests/integration/face.cpp
+++ b/tests/integration/face.cpp
@@ -68,7 +68,7 @@
 protected:
   FaceFixture()
     : face(TransportType::create(""), m_keyChain)
-    , sched(face.getIoService())
+    , sched(face.getIoContext())
   {
   }
 
@@ -82,7 +82,7 @@
   sendInterest(time::nanoseconds delay, const Interest& interest, char& outcome)
   {
     if (face2 == nullptr) {
-      face2 = make_unique<Face>(TransportType::create(""), face.getIoService(), m_keyChain);
+      face2 = make_unique<Face>(TransportType::create(""), face.getIoContext(), m_keyChain);
     }
 
     outcome = '?';
@@ -101,13 +101,13 @@
     return sendInterest(delay, interest, ignoredOutcome);
   }
 
-  /** \brief Stop io_service after a delay
+  /** \brief Stop io_context after a delay
    *  \return scheduled event id
    */
   scheduler::EventId
   terminateAfter(time::nanoseconds delay)
   {
-    return sched.schedule(delay, [this] { face.getIoService().stop(); });
+    return sched.schedule(delay, [this] { face.getIoContext().stop(); });
   }
 
 protected:
diff --git a/tests/integration/network-monitor.cpp b/tests/integration/network-monitor.cpp
index cf6d8bd..ff4d932 100644
--- a/tests/integration/network-monitor.cpp
+++ b/tests/integration/network-monitor.cpp
@@ -30,7 +30,7 @@
 #include "ndn-cxx/util/string-helper.hpp"
 #include "ndn-cxx/util/time.hpp"
 
-#include <boost/asio/io_service.hpp>
+#include <boost/asio/io_context.hpp>
 #include <iostream>
 
 namespace ndn::tests {
@@ -48,7 +48,7 @@
 
 BOOST_AUTO_TEST_CASE(Signals)
 {
-  boost::asio::io_service io;
+  boost::asio::io_context io;
   NetworkMonitor monitor(io);
 
   std::cout << "capabilities=" << AsHex{monitor.getCapabilities()} << std::endl;