Improved test coverage for django.conf.

tests/settings_tests/tests.py

@@ -3,6 +3,7 @@ import sys
 import unittest
 import warnings
 from types import ModuleType
+from unittest import mock
 
 from django.conf import ENVIRONMENT_VARIABLE, LazySettings, Settings, settings
 from django.core.exceptions import ImproperlyConfigured
@@ -11,6 +12,7 @@ from django.test import (
     SimpleTestCase, TestCase, TransactionTestCase, modify_settings,
     override_settings, signals,
 )
+from django.test.utils import requires_tz_support
 
 
 @modify_settings(ITEMS={
@@ -286,6 +288,42 @@ class SettingsTests(SimpleTestCase):
         with self.assertRaises(AttributeError):
             getattr(settings, 'TEST2')
 
+    def test_no_secret_key(self):
+        settings_module = ModuleType('fake_settings_module')
+        sys.modules['fake_settings_module'] = settings_module
+        msg = 'The SECRET_KEY setting must not be empty.'
+        try:
+            with self.assertRaisesMessage(ImproperlyConfigured, msg):
+                Settings('fake_settings_module')
+        finally:
+            del sys.modules['fake_settings_module']
+
+    def test_no_settings_module(self):
+        msg = (
+            'Requested setting%s, but settings are not configured. You '
+            'must either define the environment variable DJANGO_SETTINGS_MODULE '
+            'or call settings.configure() before accessing settings.'
+        )
+        orig_settings = os.environ[ENVIRONMENT_VARIABLE]
+        os.environ[ENVIRONMENT_VARIABLE] = ''
+        try:
+            with self.assertRaisesMessage(ImproperlyConfigured, msg % 's'):
+                settings._setup()
+            with self.assertRaisesMessage(ImproperlyConfigured, msg % ' TEST'):
+                settings._setup('TEST')
+        finally:
+            os.environ[ENVIRONMENT_VARIABLE] = orig_settings
+
+    def test_already_configured(self):
+        with self.assertRaisesMessage(RuntimeError, 'Settings already configured.'):
+            settings.configure()
+
+    @requires_tz_support
+    @mock.patch('django.conf.global_settings.TIME_ZONE', 'test')
+    def test_incorrect_timezone(self):
+        with self.assertRaisesMessage(ValueError, 'Incorrect timezone setting: test'):
+            settings._setup()
+
 
 class TestComplexSettingOverride(SimpleTestCase):
     def setUp(self):