UserManager: Fix unit test cases

User_mgr and ldap_mapper testcases are failing with D-bus errors.
This commit fixes both testcases by using mocked sdbus.

Signed-off-by: Ravi Teja <raviteja28031990@gmail.com>
Change-Id: I3fcabeb1781c938affa11a1370b107d628242374
diff --git a/test/user_mgr_test.cpp b/test/user_mgr_test.cpp
index 83ae651..88911cd 100644
--- a/test/user_mgr_test.cpp
+++ b/test/user_mgr_test.cpp
@@ -3,6 +3,7 @@
 #include <xyz/openbmc_project/Common/error.hpp>
 #include <gtest/gtest.h>
 #include <exception>
+#include <sdbusplus/test/sdbus_mock.hpp>
 
 namespace phosphor
 {
@@ -17,11 +18,12 @@
 class TestUserMgr : public testing::Test
 {
   public:
+    sdbusplus::SdBusMock sdbusMock;
     sdbusplus::bus::bus bus;
     MockManager mockManager;
 
     TestUserMgr() :
-        bus(sdbusplus::bus::new_default()), mockManager(bus, objpath)
+        bus(sdbusplus::get_mocked_new(&sdbusMock)), mockManager(bus, objpath)
     {
     }