Merge pull request #2063 from anarkiwi/master

Test stacking where redundant links are down/root dp is unreachable, …

faucet/dp.py

@@ -403,16 +403,17 @@ def make_edge_attr(edge_a, edge_z):
 
     def shortest_path(self, dest_dp):
         """Return shortest path to a DP, as a list of DPs."""
-        if self.stack is None:
-            return None
-        return networkx.shortest_path(
-            self.stack['graph'], self.name, dest_dp)
+        if self.stack is not None and 'root_dp' in self.stack:
+            return networkx.shortest_path(
+                self.stack['graph'], self.name, dest_dp)
+        return []
 
     def shortest_path_to_root(self):
         """Return shortest path to root DP, as list of DPs."""
-        if self.stack is not None:
+        # TODO: root_dp will be None, if stacking is enabled but the root DP is down.
+        if self.stack is not None and 'root_dp' in self.stack:
             root_dp = self.stack['root_dp']
-            if root_dp != self:
+            if root_dp is not None and root_dp != self:
                 return self.shortest_path(root_dp.name)
         return []
 

tests/faucet_mininet_test_unit.py

@@ -5242,11 +5242,14 @@ def setUp(self): # pylint: disable=invalid-name
             switch_to_switch_links=2)
         self.start_net()
 
-    def verify_one_stack_down(self, port_no):
+    def verify_one_stack_down(self, port_no, coldstart=False):
         self.retry_net_ping()
         self.set_port_down(port_no, wait=False)
         # self.dpids[1] is the intermediate switch.
         self.set_port_down(port_no, self.dpids[1], wait=False)
+        # test case where one link is down when coldstarted.
+        if coldstart:
+            self.coldstart_conf()
         self.retry_net_ping()
         # Broadcast works, and first switch doesn't see broadcast packet ins from stack.
         packet_in_before_broadcast = self.scrape_prometheus_var('of_vlan_packet_ins')
@@ -5258,10 +5261,12 @@ def verify_one_stack_down(self, port_no):
 
     def test_tagged(self):
         """All tagged hosts in stack topology can reach each other."""
-        self.verify_one_stack_down(self.NUM_HOSTS + 1)
+        for coldstart in (False, True):
+            self.verify_one_stack_down(self.NUM_HOSTS + 1, coldstart)
 
     def test_other_tagged(self):
-        self.verify_one_stack_down(self.NUM_HOSTS + 2)
+        for coldstart in (False, True):
+            self.verify_one_stack_down(self.NUM_HOSTS + 2, coldstart)
 
 
 class FaucetStackStringOfDPUntaggedTest(FaucetStringOfDPTest):