In tests, only set cooldown if testing it

The results for the cache unit tests were inconsistent, sometimes
blocking and other time allowing. The source of the non-determinism
was the COOLDOWN_TIME set to 2 seconds in the test. If a test took
slightly longer than the cooldown time, it would fail. Testing times
on Travis CI vary with each build, and would produce unreliable
results.

Now all tests have no cooldown period, except when the cooldown
itself is being tested. This ensures accurate and predicable test
results.

axes/test_settings.py

@@ -1,5 +1,3 @@
-from datetime import timedelta
-
 DATABASES = {
     'default': {
         'ENGINE': 'django.db.backends.sqlite3',
@@ -55,4 +53,3 @@ USE_TZ = False
 LOGIN_REDIRECT_URL = '/admin/'
 
 AXES_LOGIN_FAILURE_LIMIT = 10
-AXES_COOLOFF_TIME = timedelta(seconds=2)

axes/tests.py

@@ -16,13 +16,15 @@ from django.utils import six
 from django.test.client import RequestFactory
 
 from axes.decorators import get_ip, get_cache_key
-from axes.settings import COOLOFF_TIME
 from axes.settings import FAILURE_LIMIT
 from axes.models import AccessAttempt, AccessLog
 from axes.signals import user_locked_out
 from axes.utils import reset, iso8601
 
 
+TEST_COOLOFF_TIME = datetime.timedelta(seconds=2)
+
+
 class MockRequest:
     def __init__(self):
         self.META = dict()
@@ -140,17 +142,19 @@ class AccessAttemptTest(TestCase):
         self.assertNotEquals(AccessLog.objects.latest('id').logout_time, None)
         self.assertContains(response, 'Logged out')
 
+    @patch('axes.decorators.COOLOFF_TIME', TEST_COOLOFF_TIME)
     def test_cooling_off(self):
         """Tests if the cooling time allows a user to login
         """
         self.test_failure_limit_once()
 
         # Wait for the cooling off period
-        time.sleep(COOLOFF_TIME.total_seconds())
+        time.sleep(TEST_COOLOFF_TIME.total_seconds())
 
         # It should be possible to login again, make sure it is.
         self.test_valid_login()
 
+    @patch('axes.decorators.COOLOFF_TIME', TEST_COOLOFF_TIME)
     def test_cooling_off_for_trusted_user(self):
         """Test the cooling time for a trusted user
         """