Added a testcase to verify service password modification

      Verify Modifying Service User Password

Change-Id: I915809e147d9cfe6b5c37865bd31601df5c72b74
Signed-off-by: manashsarma <manashsarma@in.ibm.com>
diff --git a/openpower/service_account/test_service_user.robot b/openpower/service_account/test_service_user.robot
index 5527cf4..2ca71f7 100644
--- a/openpower/service_account/test_service_user.robot
+++ b/openpower/service_account/test_service_user.robot
@@ -12,8 +12,9 @@
 
 *** Test Cases ***
 
-Verify service user availability
+Verify Service User Availability
     [Documentation]  Verify service user avalability.
+    [Tags]  Verify_Service_User_Availability
 
     # Verify that service user has administrator privilege.
     ${role_config}=  Redfish_Utils.Get Attribute
@@ -24,12 +25,24 @@
 
 Verify Creating User With Service Username
     [Documentation]  Verify that user with service username can not be created.
+    [Tags]  Verify_Creating_User_With_Service_Username
 
     ${payload}=  Create Dictionary
     ...  UserName=service Password=TestPwd1  RoleId=Operator  Enabled=${True}
     Redfish.Post  /redfish/v1/AccountService/Accounts/  body=&{payload}
     ...  valid_status_codes=[${HTTP_BAD_REQUEST}]
 
+
+Verify Modifying Service User Password
+     [Documentation]  Verify error while modifying service user password in Redfish.
+     [Tags]  Verify_Modifying_Service_User_Password
+
+     ${payload}=  Create Dictionary  Password=NewTestPwd123
+     # Modification of service user password is not allowed via Redfish API.
+     Redfish.Patch  /redfish/v1/AccountService/Accounts/service  body=&{payload}
+     ...  valid_status_codes=[${HTTP_BAD_REQUEST}]
+
+
 *** Keywords ***
 
 Suite Setup Execution