tests: refactor EthernetFixture

Also, use BOOST_TEST_INFO_SCOPE in a few places.

Change-Id: I113f326207825949ed9d3d22ade0654976d49b76
diff --git a/tests/tools/nfdc/rib-module.t.cpp b/tests/tools/nfdc/rib-module.t.cpp
index b50625d..f349dfd 100644
--- a/tests/tools/nfdc/rib-module.t.cpp
+++ b/tests/tools/nfdc/rib-module.t.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2014-2022,  Regents of the University of California,
+ * Copyright (c) 2014-2023,  Regents of the University of California,
  *                           Arizona Board of Regents,
  *                           Colorado State University,
  *                           University Pierre & Marie Curie, Sorbonne University,
@@ -457,8 +457,9 @@
     ndn::nfd::RibUnregisterCommand cmd;
     cmd.validateRequest(req);
     cmd.applyDefaultsToRequest(req);
+    BOOST_TEST_INFO_SCOPE("FaceId=" << req.getFaceId());
     BOOST_CHECK_EQUAL(req.getName(), "/nm5y8X8b2");
-    BOOST_CHECK_MESSAGE(faceIds.erase(req.getFaceId()), "expected face " + to_string(req.getFaceId()));
+    BOOST_CHECK(faceIds.erase(req.getFaceId()));
     BOOST_CHECK_EQUAL(req.getOrigin(), ndn::nfd::ROUTE_ORIGIN_STATIC);
 
     this->succeedCommand(interest, req);