tests: Enable isolation of KeyChain during run of unit/integrated tests

Change-Id: Ia136e4bb074c14e8d824f563594cbc0ad7592c3b
Refs: #3655
diff --git a/tests/unit-tests/util/segment-fetcher.t.cpp b/tests/unit-tests/util/segment-fetcher.t.cpp
index 7362439..ffcc402 100644
--- a/tests/unit-tests/util/segment-fetcher.t.cpp
+++ b/tests/unit-tests/util/segment-fetcher.t.cpp
@@ -29,7 +29,7 @@
 #include "util/dummy-client-face.hpp"
 #include "security/key-chain.hpp"
 #include "lp/nack-header.hpp"
-#include "../unit-test-time-fixture.hpp"
+#include "../identity-management-time-fixture.hpp"
 #include "../make-interest-data.hpp"
 
 namespace ndn {
@@ -62,11 +62,11 @@
   }
 };
 
-class Fixture : public ndn::tests::UnitTestTimeFixture
+class Fixture : public ndn::tests::IdentityManagementTimeFixture
 {
 public:
   Fixture()
-    : face(io)
+    : face(io, m_keyChain)
     , nErrors(0)
     , nDatas(0)
     , dataSize(0)
@@ -115,7 +115,6 @@
 
 public:
   DummyClientFace face;
-  KeyChain keyChain;
 
   uint32_t nErrors;
   uint32_t lastError;