api getLastHostUpdate returns timestamp

fixes: https://pagure.io/koji/issue/2497

tests/test_cli/test_list_hosts.py

@@ -1,6 +1,8 @@
 from __future__ import absolute_import
-
 import mock
+import os
+import time
+import locale
 from six.moves import StringIO
 
 import koji
@@ -10,13 +12,51 @@ from . import utils
 
 class TestListHosts(utils.CliTestCase):
     def setUp(self):
+        # force locale to compare 'expect' value
+        locale.setlocale(locale.LC_ALL, ('en_US', 'UTF-8'))
         self.options = mock.MagicMock()
         self.options.debug = False
         self.session = mock.MagicMock()
         self.session.getAPIVersion.return_value = koji.API_VERSION
+        self.original_timezone = os.environ.get('TZ')
+        os.environ['TZ'] = 'UTC'
+        time.tzset()
+
+    def tearDown(self):
+        locale.resetlocale()
+        if self.original_timezone is None:
+            del os.environ['TZ']
+        else:
+            os.environ['TZ'] = self.original_timezone
+            time.tzset()
+
+    @mock.patch('sys.stdout', new_callable=StringIO)
+    @mock.patch('koji_cli.commands.ensure_connection')
+    def test_list_hosts_valid(self, ensure_connection, stdout):
+        host_update = 1615875554.862938
+        expected = """kojibuilder Y   Y    0.0/2.0  x86_64           Tue, 16 Mar 2021 06:19:14 UTC
+"""
+        list_hosts = [{'arches': 'x86_64',
+                       'capacity': 2.0,
+                       'comment': None,
+                       'description': None,
+                       'enabled': True,
+                       'id': 1,
+                       'name': 'kojibuilder',
+                       'ready': True,
+                       'task_load': 0.0,
+                       'user_id': 2}]
+        self.session.getLastHostUpdate.return_value = host_update
+        self.session.multiCall.return_value = [[host_update]]
+        self.session.listHosts.return_value = list_hosts
+        rv = anon_handle_list_hosts(self.options, self.session, [])
+        self.assertEqual(rv, None)
+        self.assert_console_message(stdout, expected)
+        self.session.listHosts.assert_called_once_with()
+        self.session.getLastHostUpdate.assert_called_once_with(list_hosts[0]['id'], ts=True)
 
     @mock.patch('sys.stderr', new_callable=StringIO)
-    def test_list_pkgs_non_exist_channel(self, stderr):
+    def test_list_hosts_non_exist_channel(self, stderr):
         channel = 'test-channel'
         expected = "Usage: %s list-hosts [options]\n" \
                    "(Specify the --help global option for a list of other help options)\n\n" \