auto-t: In testNetconfig add static IPv6, add comments

In static_test.py add IPv6.  Add comments on what we're actually testing
since it wasn't very clear.  After the expected ACD conflict detection,
succeed if either the lost address was removed or the client disconnected
from the AP since this seems like a correct action for netconfig to
implement.

autotests/testNetconfig/ssidTKIP.psk

@@ -1,7 +1,14 @@
 [IPv4]
+# Use a different netmask than DHCP on purpose, but use the same address
+# as DHCP would assign us to produce a conflict and test ACD
 Address=192.168.1.10
 Netmask=255.255.255.128
 Gateway=192.168.1.1
 
+[IPv6]
+# Use a different subnet than DHCP on purpose
+Address=3ffe:501:ffff:200::10/80
+Gateway=3ffe:501:ffff:200::1
+
 [Settings]
 AutoConnect=false

autotests/testNetconfig/static_test.py

@@ -16,6 +16,7 @@ import os
 class Test(unittest.TestCase):
 
     def test_connection_success(self):
+        # Use a non-default storage_dir for one of the instances, the default for the other one
         wd = IWD(True, iwd_storage_dir='/tmp/storage')
 
         ns0 = ctx.get_namespace('ns0')
@@ -46,19 +47,27 @@ class Test(unittest.TestCase):
         testutil.test_ifaces_connected()
 
         testutil.test_ip_address_match(dev1.name, '192.168.1.10', 25)
+        testutil.test_ip_address_match(dev1.name, '3ffe:501:ffff:200::10', 80)
 
         ordered_network = dev2.get_ordered_network('ssidTKIP')
 
         condition = 'not obj.connected'
         wd_ns0.wait_for_object_condition(ordered_network.network_object, condition)
 
+        # Connect to the same network from a dynamically configured client.  The
+        # DHCP server doesn't know (even though dev1 announced itself) that
+        # 192.168.1.10 is already in use and if it assigns dev2 the lowest
+        # available address, that's going to be 192.168.1.10.  dev1's ACD
+        # implementation should then stop using this address.
         ordered_network.network_object.connect()
 
         condition = 'obj.state == DeviceState.connected'
         wd_ns0.wait_for_object_condition(dev2, condition)
 
         wd.wait(1)
-        testutil.test_ip_address_match(dev1.name, None)
+        # Check dev1 is now disconnected or without its IPv4 address
+        if dev1.state == iwd.DeviceState.connected:
+            testutil.test_ip_address_match(dev1.name, None)
 
         dev1.disconnect()
         dev2.disconnect()