security: avoid parsing PIB and TPM locators multiple times

Change-Id: I2a8831e03d05b499f1f8939e03ea88cb82005743
diff --git a/tests/unit/security/key-chain.t.cpp b/tests/unit/security/key-chain.t.cpp
index ba84081..f01aab9 100644
--- a/tests/unit/security/key-chain.t.cpp
+++ b/tests/unit/security/key-chain.t.cpp
@@ -53,19 +53,7 @@
 
   ~TestHomeAndPibFixture()
   {
-    try {
-      const_cast<std::string&>(KeyChain::getDefaultPibLocator()).clear();
-    }
-    catch (const KeyChain::Error&) {
-      // ignore
-    }
-
-    try {
-      const_cast<std::string&>(KeyChain::getDefaultTpmLocator()).clear();
-    }
-    catch (const KeyChain::Error&) {
-      // ignore
-    }
+    KeyChain::resetDefaultLocators();
   }
 };
 
@@ -78,8 +66,6 @@
 {
   createClientConf({"pib=pib-memory:", "tpm=tpm-memory:"});
 
-  BOOST_REQUIRE_NO_THROW(KeyChain());
-
   KeyChain keyChain;
   BOOST_CHECK_EQUAL(keyChain.getPib().getPibLocator(), "pib-memory:");
   BOOST_CHECK_EQUAL(keyChain.getPib().getTpmLocator(), "tpm-memory:");
@@ -110,7 +96,6 @@
     unsetenv("HOME");
 #endif
 
-  BOOST_REQUIRE_NO_THROW(KeyChain());
   KeyChain keyChain;
   BOOST_CHECK_EQUAL(keyChain.getPib().getPibLocator(), "pib-memory:");
 
@@ -144,8 +129,6 @@
 {
   createClientConf({"tpm=tpm-memory:"});
 
-  BOOST_REQUIRE_NO_THROW(KeyChain());
-
   KeyChain keyChain;
   BOOST_CHECK_EQUAL(keyChain.getPib().getPibLocator(), "pib-sqlite3:");
   BOOST_CHECK_EQUAL(keyChain.getPib().getTpmLocator(), "tpm-memory:");
@@ -200,14 +183,13 @@
 
 BOOST_AUTO_TEST_CASE(KeyChainWithCustomTpmAndPib)
 {
-  BOOST_REQUIRE_NO_THROW((KeyChain("pib-memory", "tpm-memory")));
-  BOOST_REQUIRE_NO_THROW((KeyChain("pib-memory:", "tpm-memory:")));
-  BOOST_REQUIRE_NO_THROW((KeyChain("pib-memory:/something", "tpm-memory:/something")));
-
   KeyChain keyChain("pib-memory", "tpm-memory");
   BOOST_CHECK_EQUAL(keyChain.getPib().getPibLocator(), "pib-memory:");
   BOOST_CHECK_EQUAL(keyChain.getPib().getTpmLocator(), "tpm-memory:");
   BOOST_CHECK_EQUAL(keyChain.getTpm().getTpmLocator(), "tpm-memory:");
+
+  BOOST_CHECK_NO_THROW(KeyChain("pib-memory:", "tpm-memory:"));
+  BOOST_CHECK_NO_THROW(KeyChain("pib-memory:/something", "tpm-memory:/something"));
 }
 
 BOOST_FIXTURE_TEST_CASE(SigningWithCorruptedPibTpm, KeyChainFixture)