Use Boost.Operators in more places

Change-Id: I7024c3e7d4c30c99ec7a895d484f227cb60fb356
diff --git a/tests/unit/prefix-announcement.t.cpp b/tests/unit/prefix-announcement.t.cpp
index a13e9f5..a36f084 100644
--- a/tests/unit/prefix-announcement.t.cpp
+++ b/tests/unit/prefix-announcement.t.cpp
@@ -27,6 +27,10 @@
 
 namespace ndn::tests {
 
+BOOST_CONCEPT_ASSERT((boost::EqualityComparable<PrefixAnnouncement>));
+static_assert(std::is_convertible_v<PrefixAnnouncement::Error*, tlv::Error*>,
+              "PrefixAnnouncement::Error must inherit from tlv::Error");
+
 BOOST_AUTO_TEST_SUITE(TestPrefixAnnouncement)
 
 static Data