Reduce namespace nesting (ndn::ndncert -> ndncert)

Change-Id: I5b69a2c3673cccdf07ea0ba3a0e7181894328f47
diff --git a/tests/identity-management-fixture.hpp b/tests/identity-management-fixture.hpp
index 9b10dbf..7856bf9 100644
--- a/tests/identity-management-fixture.hpp
+++ b/tests/identity-management-fixture.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2020 Regents of the University of California.
+ * Copyright (c) 2013-2021 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -22,11 +22,11 @@
 #ifndef NDN_TESTS_IDENTITY_MANAGEMENT_FIXTURE_HPP
 #define NDN_TESTS_IDENTITY_MANAGEMENT_FIXTURE_HPP
 
+#include "detail/ndncert-common.hpp"
+
 #include <ndn-cxx/security/key-chain.hpp>
 #include <ndn-cxx/security/signing-helpers.hpp>
-#include <vector>
 
-namespace ndn {
 namespace ndncert {
 namespace tests {
 
@@ -51,6 +51,10 @@
  */
 class IdentityManagementFixture : public IdentityManagementBaseFixture
 {
+protected:
+  using Identity = ndn::security::Identity;
+  using Key      = ndn::security::Key;
+
 public:
   IdentityManagementFixture();
 
@@ -58,9 +62,9 @@
    * @brief Add identity @p identityName
    * @return name of the created self-signed certificate
    */
-  security::Identity
+  Identity
   addIdentity(const Name& identityName,
-              const KeyParams& params = security::KeyChain::getDefaultKeyParams());
+              const ndn::KeyParams& params = ndn::KeyChain::getDefaultKeyParams());
 
   /**
    *  @brief Save identity certificate to a file
@@ -69,7 +73,7 @@
    *  @return whether successful
    */
   bool
-  saveCertificate(const security::Identity& identity, const std::string& filename);
+  saveCertificate(const Identity& identity, const std::string& filename);
 
   /**
    * @brief Issue a certificate for \p subIdentityName signed by \p issuer
@@ -80,22 +84,21 @@
    *
    *  @return the sub identity
    */
-  security::Identity
-  addSubCertificate(const Name& subIdentityName, const security::Identity& issuer,
-                    const KeyParams& params = security::KeyChain::getDefaultKeyParams());
+  Identity
+  addSubCertificate(const Name& subIdentityName, const Identity& issuer,
+                    const ndn::KeyParams& params = ndn::KeyChain::getDefaultKeyParams());
 
   /**
    * @brief Add a self-signed certificate to @p key with issuer ID @p issuer
    */
-  security::Certificate
-  addCertificate(const security::Key& key, const std::string& issuer);
+  Certificate
+  addCertificate(const Key& key, const std::string& issuer);
 
 protected:
-  KeyChain m_keyChain;
+  ndn::KeyChain m_keyChain;
 };
 
 } // namespace tests
 } // namespace ndncert
-} // namespace ndn
 
 #endif // NDN_TESTS_IDENTITY_MANAGEMENT_FIXTURE_HPP