[VOL-3904] Added TC for OLT Grpc Channel Disconnection

Change-Id: I146c161b18cb92a4ea9759053a679511390b15cb
diff --git a/libraries/bbsim.robot b/libraries/bbsim.robot
index 3ba7bd1..ffcad0d 100755
--- a/libraries/bbsim.robot
+++ b/libraries/bbsim.robot
@@ -90,3 +90,11 @@
     @{onuList}=    Split To Lines    ${onus}
     Should Be Equal as Integers    ${rc}    0
     [Return]    ${onuList}
+
+Restart Grpc Server
+    [Documentation]  Restart Grpc Server on a BBSim OLT
+    [Arguments]    ${namespace}    ${bbsim_pod_name}    ${delay}
+    ${res}     ${rc}=    Exec Pod And Return Output And RC    ${namespace}    ${bbsim_pod_name}
+    ...    bbsimctl olt restartServer ${delay}
+    Log     ${res}
+    Should Be Equal as Integers    ${rc}    0