Hello Sai,
The sp_hadr_admin deactivate just prepares the primary site for failover, it doesn't execute the failover. After that, you need to go through few more steps until finish the failover.
Note that ideally the sp_hadr_admin stored procedure should be used in specific situations where for some reason you have some issue using DR Agent command and you need to identify which step fails, so you need to execute them one by one manually.
That's why I strongly recommend you to use the DR Agent command sap_failover for your test. It will execute all needed steps to failover , executing by himself required commands in the ASE and in the SRS in background.
Besides, the DR Agent is aimed to be used as interface to manage your HADR environment.
Please check KBA 2165143 - SAP ASE and SAP Replication Server: How to perform a planned/unplanned failover for instructions about how to perform a planned/unplanned failover.
HTH
Regards,
Cris