Unit Test: Adding unit test cases UsrMgr

This changes set will add needed unit test cases for User Manager

Change-Id: I848cdbde528d41c2a09abcf35527044b6084f023
Signed-off-by: Abhilash Raju <abhilash.kollam@gmail.com>
diff --git a/test/mock_user_mgr.hpp b/test/mock_user_mgr.hpp
index 99f2b37..b301ba7 100644
--- a/test/mock_user_mgr.hpp
+++ b/test/mock_user_mgr.hpp
@@ -25,6 +25,15 @@
 
     friend class TestUserMgr;
 };
-
+class MockUser : public Users
+{
+  public:
+    MockUser(sdbusplus::bus::bus& bus, const char* objPath,
+             std::vector<std::string> groupNames, const std::string& priv,
+             bool enabled, UserMgr& parent) :
+        Users(bus, objPath, groupNames, priv, enabled, parent)
+    {}
+    MOCK_METHOD0(createSecretKey, std::string());
+};
 } // namespace user
 } // namespace phosphor