tests: sync common testing infrastructure with ndn-cxx

Upgrade waf to version 2.0.21

Change-Id: I30615cc49416088e9c5e4d602fd11360c0ed9328
diff --git a/tests/unit/database-test-data.hpp b/tests/unit/database-test-data.hpp
index f1ff278..a7a9668 100644
--- a/tests/unit/database-test-data.hpp
+++ b/tests/unit/database-test-data.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2014-2017, Regents of the University of California.
+ * Copyright (c) 2014-2020, Regents of the University of California.
  *
  * This file is part of NDNS (Named Data Networking Domain Name Service).
  * See AUTHORS.md for complete list of NDNS authors and contributors.
@@ -25,13 +25,14 @@
 #include "clients/query.hpp"
 #include "validator/validator.hpp"
 
-#include "test-common.hpp"
+#include "io-fixture.hpp"
+#include "key-chain-fixture.hpp"
 
 namespace ndn {
 namespace ndns {
 namespace tests {
 
-class DbTestData : public IdentityManagementFixture, public UnitTestTimeFixture
+class DbTestData : public IoFixture, public KeyChainFixture
 {
 public:
   static const boost::filesystem::path TEST_DATABASE;
@@ -41,7 +42,7 @@
 
   DbTestData();
 
-  ~DbTestData();
+  ~DbTestData() override;
 
 private:
   void