diff --git a/formtools/templates/404.html b/formtools/templates/404.html
new file mode 100644
index 0000000..4aa1203
--- /dev/null
+++ b/formtools/templates/404.html
@@ -0,0 +1 @@
+Not found.
diff --git a/formtools/tests/__init__.py b/formtools/tests/__init__.py
index d659403..e628690 100644
--- a/formtools/tests/__init__.py
+++ b/formtools/tests/__init__.py
@@ -7,6 +7,7 @@ from django.conf import settings
 from django.contrib.formtools import preview, utils
 from django.contrib.formtools.wizard import FormWizard
 from django.test import TestCase
+from django.test.utils import override_settings
 from django.utils import unittest
 
 from django.contrib.formtools.tests.wizard import *
@@ -29,19 +30,12 @@ class TestFormPreview(preview.FormPreview):
     def done(self, request, cleaned_data):
         return http.HttpResponse(success_string)
 
-
-class FormToolsTestCase(TestCase):
-    def setUp(self):
-        # in the test runner use templates/tests/ to provide base.html
-        self.old_TEMPLATE_DIRS = settings.TEMPLATE_DIRS
-        settings.TEMPLATE_DIRS = list(settings.TEMPLATE_DIRS) + [
-            os.path.join(os.path.dirname(__file__), 'templates')]
-
-    def tearDown(self):
-        settings.TEMPLATE_DIRS = self.old_TEMPLATE_DIRS
-
-
-class PreviewTests(FormToolsTestCase):
+@override_settings(
+    TEMPLATE_DIRS=(
+        os.path.join(os.path.dirname(__file__), 'templates'),
+    ),
+)
+class PreviewTests(TestCase):
     urls = 'django.contrib.formtools.tests.urls'
 
     def setUp(self):
@@ -215,7 +209,13 @@ class DummyRequest(http.HttpRequest):
         self._dont_enforce_csrf_checks = True
 
 
-class WizardTests(FormToolsTestCase):
+@override_settings(
+    SECRET_KEY="123",
+    TEMPLATE_DIRS=(
+        os.path.join(os.path.dirname(__file__), 'templates'),
+    ),
+)
+class WizardTests(TestCase):
     urls = 'django.contrib.formtools.tests.urls'
     input_re = re.compile('name="([^"]+)" value="([^"]+)"')
     wizard_step_data = (
@@ -232,16 +232,6 @@ class WizardTests(FormToolsTestCase):
         }
     )
 
-    def setUp(self):
-        super(WizardTests, self).setUp()
-        # Use a known SECRET_KEY to make security_hash tests deterministic
-        self.old_SECRET_KEY = settings.SECRET_KEY
-        settings.SECRET_KEY = "123"
-
-    def tearDown(self):
-        super(WizardTests, self).tearDown()
-        settings.SECRET_KEY = self.old_SECRET_KEY
-
     def test_step_starts_at_zero(self):
         """
         step should be zero for the first form