Add unit tests to ensure TZ variable remains set

See review https://review.openstack.org/29836.

Change-Id: I8ec80202789707f723abfe93ccc9cf1e677e4dc6
Signed-off-by: Peter Portante <peter.portante@redhat.com>

swift/common/daemon.py

@@ -15,6 +15,7 @@
 
 import os
 import sys
+import time
 import signal
 from re import sub
 
@@ -99,6 +100,12 @@ def run_daemon(klass, conf_file, section_name='', once=False, **kwargs):
     eventlet_debug = utils.config_true_value(conf.get('eventlet_debug', 'no'))
     eventlet.debug.hub_exceptions(eventlet_debug)
 
+    # Ensure TZ environment variable exists to avoid stat('/etc/localtime') on
+    # some platforms. This locks in reported times to the timezone in which
+    # the server first starts running in locations that periodically change
+    # timezones.
+    os.environ['TZ'] = time.strftime("%z", time.gmtime())
+
     try:
         klass(conf).run(once=once, **kwargs)
     except KeyboardInterrupt:

swift/common/wsgi.py

@@ -190,6 +190,12 @@ class RestrictedGreenPool(GreenPool):
 
 
 def run_server(conf, logger, sock):
+    # Ensure TZ environment variable exists to avoid stat('/etc/localtime') on
+    # some platforms. This locks in reported times to the timezone in which
+    # the server first starts running in locations that periodically change
+    # timezones.
+    os.environ['TZ'] = time.strftime("%z", time.gmtime())
+
     wsgi.HttpProtocol.default_request_version = "HTTP/1.0"
     # Turn off logging requests by the underlying WSGI software.
     wsgi.HttpProtocol.log_request = lambda *a: None
@@ -245,12 +251,6 @@ def run_wsgi(conf_path, app_section, *args, **kwargs):
     # redirect errors to logger and close stdio
     capture_stdio(logger)
 
-    # Ensure TZ environment variable exists to avoid stat('/etc/localtime') on
-    # some platforms. This locks in reported times to the timezone in which
-    # the server first starts running in locations that periodically change
-    # timezones.
-    os.environ['TZ'] = time.strftime("%z", time.gmtime())
-
     worker_count = int(conf.get('workers', '1'))
     # Useful for profiling [no forks].
     if worker_count == 0:

test/unit/common/test_daemon.py

@@ -15,11 +15,13 @@
 
 # TODO: Test kill_children signal handlers
 
+import os
 import unittest
 from getpass import getuser
 import logging
 from StringIO import StringIO
 from test.unit import tmpfile
+from mock import patch
 
 from swift.common import daemon, utils
 
@@ -85,8 +87,10 @@ class TestRunDaemon(unittest.TestCase):
 user = %s
 """ % getuser()
         with tmpfile(sample_conf) as conf_file:
+            with patch.dict('os.environ', {'TZ': ''}):
                 daemon.run_daemon(MyDaemon, conf_file)
                 self.assertEquals(MyDaemon.forever_called, True)
+                self.assert_(os.environ['TZ'] is not '')
             daemon.run_daemon(MyDaemon, conf_file, once=True)
             self.assertEquals(MyDaemon.once_called, True)
 

test/unit/common/test_wsgi.py

@@ -360,10 +360,12 @@ class TestWSGI(unittest.TestCase):
             _fake_rings(conf_root)
             with patch('swift.common.wsgi.wsgi') as _wsgi:
                 with patch('swift.common.wsgi.eventlet') as _eventlet:
+                    with patch.dict('os.environ', {'TZ': ''}):
                         conf = wsgi.appconfig(conf_dir)
                         logger = logging.getLogger('test')
                         sock = listen(('localhost', 0))
                         wsgi.run_server(conf, logger, sock)
+                        self.assert_(os.environ['TZ'] is not '')
 
         self.assertEquals('HTTP/1.0',
                           _wsgi.HttpProtocol.default_request_version)