tests: refactor common test infrastructure and fixtures

Change-Id: I597c11130eefa2cc2846ee6655c85dc04f2f22ef
diff --git a/tests/unit/security/validator-config/checker.t.cpp b/tests/unit/security/validator-config/checker.t.cpp
index 55e48a1..029996c 100644
--- a/tests/unit/security/validator-config/checker.t.cpp
+++ b/tests/unit/security/validator-config/checker.t.cpp
@@ -39,7 +39,7 @@
 BOOST_AUTO_TEST_SUITE(Security)
 BOOST_AUTO_TEST_SUITE(ValidatorConfig)
 
-class CheckerFixture : public IdentityManagementFixture
+class CheckerFixture : public KeyChainFixture
 {
 public:
   CheckerFixture()