Added link local persistency on bmc reboot test

Changes:
    - Added the test case:
    Verify persistency of link local on bmc reboot

    Tested:
        Ran and Tested on BMC Environment.

Change-Id: Ieee7d4023afca35b446167b1a92f22b0a17ca17a
Signed-off-by: Abhijith Naik <Abhijith.Naik@ibm.com>
diff --git a/redfish/managers/test_bmc_ipv6.robot b/redfish/managers/test_bmc_ipv6.robot
index 42083b0..6f54b79 100644
--- a/redfish/managers/test_bmc_ipv6.robot
+++ b/redfish/managers/test_bmc_ipv6.robot
@@ -255,6 +255,25 @@
     Should Be Equal    ${linklocal_interface_id}    ${slaac_interface_id}
 
 
+Verify Persistency Of Link Local IPv6 On BMC Reboot
+    [Documentation]  Verify persistency of link local on BMC reboot.
+    [Tags]  Verify_Persistency_Of_Link_Local_IPv6_On_BMC_Reboot
+
+    # Capturing the linklocal before reboot.
+    @{ipv6_address_origin_list}  ${linklocal_addr_before_reboot}=
+    ...  Get Address Origin List And Address For Type  LinkLocal
+
+    # Rebooting BMC.
+    Redfish OBMC Reboot (off)  stack_mode=skip
+
+    @{ipv6_address_origin_list}  ${linklocal_addr_after_reboot}=
+    ...  Get Address Origin List And Address For Type  LinkLocal
+
+    # Verifying the linklocal must be the same before and after reboot.
+    Should Be Equal    ${linklocal_addr_before_reboot}    ${linklocal_addr_after_reboot}
+    ...    msg=IPv6 Linklocal address has changed after reboot.
+
+
 *** Keywords ***
 
 Suite Setup Execution