Fix shutdown/startup flow in test_reset to support multi-asic

tests/platform_tests/api/test_sfp.py

@@ -371,6 +371,27 @@ def get_interfaces_to_flap_after_sfp_reset(self, port_index_to_info_dict, duthos
                 interfaces_to_flap.append(intf)
         return interfaces_to_flap
 
+    def _shutdown_and_no_shutdown_ports(self, duthost, intf_list):
+        intf_to_flap_joined = ",".join(intf_list)
+        try:
+            if duthost.is_multi_asic:
+                for intf in intf_list:
+                    duthost.shutdown_interface(intf)
+            else:
+                duthost.shutdown_interface(intf_to_flap_joined)
+        except Exception as e:
+            logger.error("Failed to shutdown interfaces: {}".format(e))
+
+        shutdown_wait_scale_factor = max(1, len(intf_list)*0.01)
+        time.sleep(WAIT_TIME_AFTER_INTF_SHUTDOWN*shutdown_wait_scale_factor)
+        try:
+            if duthost.is_multi_asic:
+                for intf in intf_list:
+                    duthost.no_shutdown_interface(intf)
+            else:
+                duthost.no_shutdown_interface(intf_to_flap_joined)
+        except Exception as e:
+            logger.error("Failed to startup interfaces: {}".format(e))
     #
     # Functions to test methods inherited from DeviceBase class
     #
@@ -744,18 +765,8 @@ def test_reset(self,
         time.sleep(I2C_WAIT_TIME_AFTER_SFP_RESET)
         intf_list = self.get_interfaces_to_flap_after_sfp_reset(port_index_to_info_dict, duthost)
         if intf_list:
-            intf_to_flap_joined = ",".join(intf_list)
-            logger.info("Flapping interfaces: {}".format(intf_to_flap_joined))
-            try:
-                duthost.shutdown_interface(intf_to_flap_joined)
-            except Exception as e:
-                logger.error("Failed to shutdown interfaces: {}".format(e))
-            shutdown_wait_scale_factor = max(1, len(intf_list)*0.01)
-            time.sleep(WAIT_TIME_AFTER_INTF_SHUTDOWN*shutdown_wait_scale_factor)
-            try:
-                duthost.no_shutdown_interface(intf_to_flap_joined)
-            except Exception as e:
-                logger.error("Failed to startup interfaces: {}".format(e))
+            logger.info("Flapping interfaces: {}".format(intf_list))
+            self._shutdown_and_no_shutdown_ports(duthost, intf_list)
             _, port_up_wait_time = default_port_toggle_wait_time(duthost, len(intf_list))
             if not wait_until(port_up_wait_time, 10, 0,
                               check_interface_status_of_up_ports, duthost):