style: made container APIs more consistent.

Change-Id: Ib4feedfc4c9fb497dfcd67e7e6a33ee03db58d7f
refs: #4337
diff --git a/tests/update/test-prefix-update-processor.cpp b/tests/update/test-prefix-update-processor.cpp
index 42d9fa0..8fb4c27 100644
--- a/tests/update/test-prefix-update-processor.cpp
+++ b/tests/update/test-prefix-update-processor.cpp
@@ -252,7 +252,7 @@
 
   NamePrefixList& namePrefixList = nlsr.getNamePrefixList();
 
-  BOOST_REQUIRE_EQUAL(namePrefixList.getSize(), 1);
+  BOOST_REQUIRE_EQUAL(namePrefixList.size(), 1);
   BOOST_CHECK_EQUAL(namePrefixList.getNames().front(), parameters.getName());
 
   BOOST_CHECK(wasRoutingUpdatePublished());
@@ -271,7 +271,7 @@
   face.receive(*withdrawInterest);
   this->advanceClocks(ndn::time::milliseconds(10));
 
-  BOOST_CHECK_EQUAL(namePrefixList.getSize(), 0);
+  BOOST_CHECK_EQUAL(namePrefixList.size(), 0);
 
   BOOST_CHECK(wasRoutingUpdatePublished());
   BOOST_CHECK(nameLsaSeqNoBeforeInterest < nlsr.getLsdb().getSequencingManager().getNameLsaSeq());