diff --git a/test/user_mgr_test.cpp b/test/user_mgr_test.cpp
index 588c2fa..16d6617 100644
--- a/test/user_mgr_test.cpp
+++ b/test/user_mgr_test.cpp
@@ -253,6 +253,12 @@
         // Set config files to test files
         pamPasswdConfigFile = tempPamConfigFile;
         pamAuthConfigFile = tempPamConfigFile;
+
+        ON_CALL(*this, executeUserAdd).WillByDefault(testing::Return());
+
+        ON_CALL(*this, executeUserDelete).WillByDefault(testing::Return());
+
+        ON_CALL(*this, getIpmiUsersCount).WillByDefault(testing::Return(0));
     }
 
     ~UserMgrInTest() override
@@ -260,6 +266,13 @@
         EXPECT_NO_THROW(removeFile(tempPamConfigFile));
     }
 
+    MOCK_METHOD(void, executeUserAdd, (const char*, const char*, bool, bool),
+                (override));
+
+    MOCK_METHOD(void, executeUserDelete, (const char*), (override));
+
+    MOCK_METHOD(size_t, getIpmiUsersCount, (), (override));
+
   protected:
     static sdbusplus::bus_t busInTest;
     std::string tempPamConfigFile;
@@ -360,5 +373,54 @@
         sdbusplus::xyz::openbmc_project::Common::Error::InvalidArgument);
 }
 
+TEST_F(UserMgrInTest, UserAddNotRootFailedWithInternalFailure)
+{
+    EXPECT_THROW(
+        UserMgr::executeUserAdd("user0", "ipmi,ssh", true, true),
+        sdbusplus::xyz::openbmc_project::Common::Error::InternalFailure);
+}
+
+TEST_F(UserMgrInTest, UserDeleteNotRootFailedWithInternalFailure)
+{
+    EXPECT_THROW(
+        UserMgr::executeUserDelete("user0"),
+        sdbusplus::xyz::openbmc_project::Common::Error::InternalFailure);
+}
+
+TEST_F(UserMgrInTest,
+       ThrowForMaxGrpUserCountThrowsNoResourceWhenIpmiUserExceedLimit)
+{
+    EXPECT_CALL(*this, getIpmiUsersCount()).WillOnce(Return(ipmiMaxUsers));
+    EXPECT_THROW(
+        throwForMaxGrpUserCount({"ipmi"}),
+        sdbusplus::xyz::openbmc_project::User::Common::Error::NoResource);
+}
+
+TEST_F(UserMgrInTest, CreateUserThrowsInternalFailureWhenExecuteUserAddFails)
+{
+    EXPECT_CALL(*this, executeUserAdd)
+        .WillOnce(testing::Throw(
+            sdbusplus::xyz::openbmc_project::Common::Error::InternalFailure()));
+    EXPECT_THROW(
+        createUser("whatever", {"redfish"}, "", true),
+        sdbusplus::xyz::openbmc_project::Common::Error::InternalFailure);
+}
+
+TEST_F(UserMgrInTest, DeleteUserThrowsInternalFailureWhenExecuteUserDeleteFails)
+{
+    std::string username = "user";
+    EXPECT_NO_THROW(
+        UserMgr::createUser(username, {"redfish", "ssh"}, "priv-user", true));
+    EXPECT_CALL(*this, executeUserDelete(testing::StrEq(username)))
+        .WillOnce(testing::Throw(
+            sdbusplus::xyz::openbmc_project::Common::Error::InternalFailure()))
+        .WillOnce(testing::DoDefault());
+
+    EXPECT_THROW(
+        deleteUser(username),
+        sdbusplus::xyz::openbmc_project::Common::Error::InternalFailure);
+    EXPECT_NO_THROW(UserMgr::deleteUser(username));
+}
+
 } // namespace user
 } // namespace phosphor