routeros_facts: fix crash when ipv6 is disabled (#39)

* routeros_facts: fix crash when ipv6 is disabled

* chore: rename fixture file

plugins/modules/network/routeros/routeros_facts.py

@@ -289,6 +289,8 @@ class Interfaces(FactsBase):
 
     def populate_ipv6_interfaces(self, data):
         for key, value in iteritems(data):
+            if key is None:
+                break
             if 'ipv6' not in self.facts['interfaces'][key]:
                 self.facts['interfaces'][key]['ipv6'] = list()
             addr, subnet = value['address'].split("/")

tests/unit/modules/network/routeros/fixtures/routeros_facts/ipv6_address_print_detail_without-paging_no-ipv6

@@ -0,0 +1 @@
+bad command name address (line 1 column 7)

tests/unit/modules/network/routeros/test_routeros_facts.py

@@ -107,3 +107,13 @@ class TestRouterosFactsModule(TestRouterosModule):
         self.assertEqual(
             len(result['ansible_facts']['ansible_net_neighbors'].keys()), 4
         )
+
+    def test_routeros_facts_interfaces_no_ipv6(self):
+        fixture = load_fixture(
+            'routeros_facts/ipv6_address_print_detail_without-paging_no-ipv6'
+        )
+        interfaces = self.module.Interfaces(module=self.module)
+        addresses = interfaces.parse_addresses(data=fixture)
+        result = interfaces.populate_ipv6_interfaces(data=addresses)
+
+        self.assertEqual(result, None)