[advanced-reboot] Fix testing hang when doing BGP shutdown on Arista VM

ansible/roles/test/files/ptftests/arista.py

@@ -64,6 +64,9 @@ def connect(self):
         self.do_cmd('enable')
         self.do_cmd('terminal length 0')
 
+        version_output = self.do_cmd('show version')
+        self.veos_version = self.parse_version(version_output)
+
         return self.shell
 
     def get_arista_prompt(self, first_prompt):
@@ -373,7 +376,16 @@ def change_bgp_neigh_state(self, asn, is_up=True):
         state = ['shut', 'no shut']
         self.do_cmd('configure')
         self.do_cmd('router bgp %s' % asn)
-        self.do_cmd('%s' % state[is_up])
+        if self.veos_version < 4.20:
+            self.do_cmd('%s' % state[is_up])
+        else:
+            if is_up == True:
+                self.do_cmd('%s' % state[is_up])
+            else:
+                # shutdown BGP will pop confirm message, the message is 
+                # "You are attempting to shutdown BGP. Are you sure you want to shutdown? [confirm]"
+                self.do_cmd('%s' % state[is_up], prompt = '[confirm]')
+                self.do_cmd('y')
         self.do_cmd('exit')
         self.do_cmd('exit')
 
@@ -525,3 +537,10 @@ def check_change_time(self, output, entity, what):
 
         # Note: the first item is a placeholder
         return 0, change_count
+
+    def parse_version(self, output):
+        version = 0
+        for line in output.split('\n'):
+            if ('Software image version: ' in line):
+                version = float(re.search('([1-9]{1}\d*)(\.\d{0,2})', line).group())
+        return version