Fix alarm-definition-list in Python 3

Python 3 uses unicode strings by default. This bug was caused by
attempting to join a byte string to a unicode string when running
with the Python 3 interpreter.

A unit test was added to reproduce the problem.

Whilst this fix allows alarm definitions to be listed, it doesn't
fix the formatting problem in Python 3. A better fix may be
to return unicode strings in Python 3 as part of a wider code
audit.

Story: 2004972
Task: 29427
Change-Id: Ib008ed2aacd93f499b15094cf5a7e1bb0bb50a1f

monascaclient/common/utils.py

@@ -198,4 +198,4 @@ def format_list(in_list):
         else:
             key = k
         string_list.append(key)
-    return '\n'.join(string_list)
+    return b'\n'.join(string_list)

monascaclient/tests/v2_0/shell/test_alarm_definitions.py

@@ -71,6 +71,37 @@ class TestAlarmDefinitionShellV2(base.BaseTestCase):
             undetermined_actions=[ad_action_id]
         )
 
+    @mock.patch('monascaclient.osc.migration.make_client')
+    def test_alarm_definitions_list(self, mc):
+        mc.return_value = c = FakeV2Client()
+
+        c.alarm_definitions.list.return_value = [{
+            "name": "ntp_sync_check",
+            "id": "aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee",
+            "expression": "(max(ntp.offset{}, deterministic)>=1)",
+            "match_by": ['hostname'],
+            "description": "NTP time sync check",
+            "actions_enabled": True,
+            "deterministic": True,
+            "alarm_actions": ['aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee'],
+            "ok_actions": [],
+            "undetermined_actions": [],
+            "severity": "HIGH",
+        }]
+
+        name, cmd_class = migr.create_command_class(
+            'do_alarm_definition_list',
+            shell
+        )
+        cmd = cmd_class(mock.Mock(), mock.Mock())
+
+        parser = cmd.get_parser(name)
+        raw_args = []
+        parsed_args = parser.parse_args(raw_args)
+        cmd.run(parsed_args)
+
+        c.alarm_definitions.list.assert_called_once()
+
     @mock.patch('monascaclient.osc.migration.make_client')
     def test_should_patch_name(self, mc):
         ad_id = '0495340b-58fd-4e1c-932b-5e6f9cc96490'