diff --git a/constance/config.py b/constance/config.py
index c272802..0bf670a 100644
--- a/constance/config.py
+++ b/constance/config.py
@@ -23,7 +23,10 @@ class Config(object):
             super(Config, self).__setattr__('_rd', redis.Redis(**settings.CONSTANCE_CONNECTION))
 
     def __getattr__(self, key):
-        default, help_text = settings.CONSTANCE_CONFIG[key]
+        try:
+            default, help_text = settings.CONSTANCE_CONFIG[key]
+        except KeyError, e:
+            raise AttributeError(key)
         result = self._rd.get("%s%s" % (self._prefix, key))
         if result is None:
             result = default
@@ -32,6 +35,8 @@ class Config(object):
         return loads(result)
 
     def __setattr__(self, key, value):
+        if key not in settings.CONSTANCE_CONFIG:
+            raise AttributeError(key)
         self._rd.set("%s%s" % (self._prefix, key), dumps(value))
 
     def __dir__(self):
diff --git a/constance/tests/__init__.py b/constance/tests/__init__.py
deleted file mode 100644
index 2276fe6..0000000
--- a/constance/tests/__init__.py
+++ /dev/null
@@ -1 +0,0 @@
-from constance.tests.test_config import *
diff --git a/constance/tests/test_config.py b/constance/tests/test_config.py
deleted file mode 100644
index 43f79e0..0000000
--- a/constance/tests/test_config.py
+++ /dev/null
@@ -1,21 +0,0 @@
-from django.test import TestCase
-from django.conf import settings
-
-from constance import config
-
-
-
-class TestStorage(TestCase):
-
-    def test_store(self):
-        # read defaults
-        self.assertEquals(config.INT_VALUE, 1)
-        self.assertEquals(config.BOOL_VALUE, True)
-        self.assertEquals(config.STRING_VALUE, 'Hello world')
-
-        config.INT_VALUE = 100
-        config.BOOL_VALUE = False
-
-        self.assertEquals(config.INT_VALUE, 100)
-        self.assertEquals(config.BOOL_VALUE, False)
-        self.assertEquals(config.STRING_VALUE, 'Hello world')
diff --git a/constance/tests/test_settings.py b/constance/tests/test_settings.py
deleted file mode 100644
index 07402b0..0000000
--- a/constance/tests/test_settings.py
+++ /dev/null
@@ -1,7 +0,0 @@
-CONSTANCE_CONFIG = {
-    'INT_VALUE': (1, 'some int'),
-    'BOOL_VALUE': (True, 'true or false'),
-    'STRING_VALUE': ('Hello world', 'greetings'),
-}
-
-CONSTANCE_CONNECTION_CLASS = 'redis_mockup.Connection'
diff --git a/tests/__init__.py b/tests/__init__.py
new file mode 100644
index 0000000..8b13789
--- /dev/null
+++ b/tests/__init__.py
@@ -0,0 +1 @@
+
diff --git a/tests/models.py b/tests/models.py
new file mode 100644
index 0000000..e69de29
diff --git a/constance/tests/redis_mockup.py b/tests/redis_mockup.py
similarity index 100%
rename from constance/tests/redis_mockup.py
rename to tests/redis_mockup.py
diff --git a/constance/tests/runtests.py b/tests/runtests.py
similarity index 95%
rename from constance/tests/runtests.py
rename to tests/runtests.py
index 7a302fc..9258151 100644
--- a/constance/tests/runtests.py
+++ b/tests/runtests.py
@@ -1,4 +1,3 @@
-#!/usr/bin/env python
 
 """Borrowed from Carl Meyer's django-adminfiles."""
 
@@ -11,6 +10,7 @@ os.environ['DJANGO_SETTINGS_MODULE'] = 'tests.test_settings'
 
 from django.test.simple import run_tests
 
+
 def runtests():
     failures = run_tests(['tests'], verbosity=1, interactive=True)
     sys.exit(failures)
diff --git a/tests/test_config.py.orig b/tests/test_config.py.orig
new file mode 100644
index 0000000..128d8f9
--- /dev/null
+++ b/tests/test_config.py.orig
@@ -0,0 +1,49 @@
+from django.test import TestCase
+from django.conf import settings
+
+from constance import config
+
+
+
+class TestStorage(TestCase):
+
+    def setUp(self):
+        self.old_config = getattr(settings, 'CONSTANCE_CONFIG', None)
+        settings.CONSTANCE_CONFIG = {
+            'INT_VALUE': (1, 'some int'),
+            'BOOL_VALUE': (True, 'true or false'),
+            'STRING_VALUE': ('Hello world', 'greetings'),
+        }
+        config._rd.clear()
+
+    def test_store(self):
+        # read defaults
+        self.assertEquals(config.INT_VALUE, 1)
+        self.assertEquals(config.BOOL_VALUE, True)
+        self.assertEquals(config.STRING_VALUE, 'Hello world')
+
+        # set values
+        config.INT_VALUE = 100
+        config.BOOL_VALUE = False
+
+        # read again
+        self.assertEquals(config.INT_VALUE, 100)
+        self.assertEquals(config.BOOL_VALUE, False)
+        self.assertEquals(config.STRING_VALUE, 'Hello world')
+
+    def test_nonexistent(self):
+        try:
+            config.NON_EXISTENT
+        except Exception, e:
+            pass
+        self.assertEquals(type(e), AttributeError)
+
+        try:
+            config.NON_EXISTENT = 1
+        except Exception, e:
+            pass
+        self.assertEquals(type(e), AttributeError)
+
+    def tearDown(self):
+        if self.old_config:
+            settings.CONSTANCE_CONFIG = self.old_config
diff --git a/tests/test_settings.py b/tests/test_settings.py
new file mode 100644
index 0000000..47c64fd
--- /dev/null
+++ b/tests/test_settings.py
@@ -0,0 +1,14 @@
+DATABASES = {
+    'default': {
+        'ENGINE': 'django.db.backends.sqlite3',
+    }
+}
+
+
+CONSTANCE_CONNECTION_CLASS = 'tests.redis_mockup.Connection'
+
+INSTALLED_APPS = (
+    'tests',
+    'constance',
+)
+
diff --git a/tests/tests.py b/tests/tests.py
new file mode 100644
index 0000000..128d8f9
--- /dev/null
+++ b/tests/tests.py
@@ -0,0 +1,49 @@
+from django.test import TestCase
+from django.conf import settings
+
+from constance import config
+
+
+
+class TestStorage(TestCase):
+
+    def setUp(self):
+        self.old_config = getattr(settings, 'CONSTANCE_CONFIG', None)
+        settings.CONSTANCE_CONFIG = {
+            'INT_VALUE': (1, 'some int'),
+            'BOOL_VALUE': (True, 'true or false'),
+            'STRING_VALUE': ('Hello world', 'greetings'),
+        }
+        config._rd.clear()
+
+    def test_store(self):
+        # read defaults
+        self.assertEquals(config.INT_VALUE, 1)
+        self.assertEquals(config.BOOL_VALUE, True)
+        self.assertEquals(config.STRING_VALUE, 'Hello world')
+
+        # set values
+        config.INT_VALUE = 100
+        config.BOOL_VALUE = False
+
+        # read again
+        self.assertEquals(config.INT_VALUE, 100)
+        self.assertEquals(config.BOOL_VALUE, False)
+        self.assertEquals(config.STRING_VALUE, 'Hello world')
+
+    def test_nonexistent(self):
+        try:
+            config.NON_EXISTENT
+        except Exception, e:
+            pass
+        self.assertEquals(type(e), AttributeError)
+
+        try:
+            config.NON_EXISTENT = 1
+        except Exception, e:
+            pass
+        self.assertEquals(type(e), AttributeError)
+
+    def tearDown(self):
+        if self.old_config:
+            settings.CONSTANCE_CONFIG = self.old_config