Merge ~adam-collard/maas:2.9-flaky-test-collision-avoidance into maas:2.9

[Adam Collard]

Update test fixture to ensure tested IPs are different

By using factory.pick_ip_in_network() twice in one test, it's possible
for the two IPs to be the same. This then causes the test to fail
since there won't be an update to fire the trigger.

Cherry-pick 3bd3539d831969eb135a5b2928c37cb04ba17fc6

[Adam Collard (adam-collard)]

review: Approve

diff --git a/src/maasserver/triggers/tests/test_system_listener.py b/src/maasserver/triggers/tests/test_system_listener.py
index be1d117..1573f02 100644
--- a/src/maasserver/triggers/tests/test_system_listener.py
+++ b/src/maasserver/triggers/tests/test_system_listener.py
@@ -3834,7 +3834,9 @@ class TestDNSStaticIPAddressListener(
                 "ip": old_ip,
             },
         )
-        new_ip = factory.pick_ip_in_network(subnet.get_ipnetwork())
+        new_ip = factory.pick_ip_in_network(
+            subnet.get_ipnetwork(), but_not=[old_ip]
+        )
         yield self.capturePublication()
         dv = DeferredValue()
         listener = self.make_listener_without_delay()
@@ -3875,7 +3877,9 @@ class TestDNSStaticIPAddressListener(
                 "ip": old_ip,
             },
         )
-        new_ip = factory.pick_ip_in_network(subnet.get_ipnetwork())
+        new_ip = factory.pick_ip_in_network(
+            subnet.get_ipnetwork(), but_not=[old_ip]
+        )
         yield self.capturePublication()
         dv = DeferredValue()
         listener = self.make_listener_without_delay()