diff --git a/dav_base/tests/generic.py b/dav_base/tests/generic.py
index 7d50050..1c92a6b 100644
--- a/dav_base/tests/generic.py
+++ b/dav_base/tests/generic.py
@@ -4,6 +4,7 @@ from django.apps import apps
 from django.contrib.auth.models import AbstractUser
 from django.contrib.staticfiles.testing import StaticLiveServerTestCase
 from django.core import mail as django_mail
+from django.core.exceptions import ValidationError
 from django.test import SimpleTestCase, TestCase, tag
 from django.urls import reverse
 from selenium import webdriver
@@ -209,6 +210,24 @@ class UrlsTestCase(SimpleTestCase):
                                      'Getting url named \'{}\' resolve to wrong function'.format(url.name))
 
 
+class ValidatorTestMixin(object):
+    def assertValid(self, validator, data):
+        for val in data:
+            try:
+                validator(val)
+            except ValidationError as e:  # pragma: no cover
+                self.fail('%s: %s' % (val, e))
+
+    def assertInvalid(self, validator, data):
+        for val in data:
+            try:
+                validator(val)
+            except ValidationError:
+                pass
+            else:  # pragma: no cover
+                self.fail('%s: no ValidationError was raised' % val)
+
+
 class SeleniumTestCase(StaticLiveServerTestCase):
     headless = True
     window_width = 1024
diff --git a/dav_registration/tests/test_validators.py b/dav_registration/tests/test_validators.py
index d9acbb5..a7d8e2d 100644
--- a/dav_registration/tests/test_validators.py
+++ b/dav_registration/tests/test_validators.py
@@ -1,12 +1,15 @@
-from django.core.exceptions import ValidationError
 from django.test import SimpleTestCase
 
+from dav_base.tests.generic import ValidatorTestMixin
+
 from ..validators import DAVNumberValidator
 
 
-class TestCase(SimpleTestCase):
-    def test_dav_number_validator(self):
-        valid_data = (
+class DAVNumberValidatorTestCase(ValidatorTestMixin, SimpleTestCase):
+    validator = DAVNumberValidator
+
+    def test_valid_data(self):
+        data = (
             '131/00/1',
             '1',
             '22',
@@ -19,7 +22,10 @@ class TestCase(SimpleTestCase):
             '54321*54321*4321*4321',
             '54321*54321*4321*4321*87654321',
         )
-        invalid_data = (
+        self.assertValid(self.validator, data)
+
+    def test_invalid_data(self):
+        data = (
             '131/00/',
             '1/1/1',
             '1/1',
@@ -28,19 +34,4 @@ class TestCase(SimpleTestCase):
             'abc/00/131',
             '131/ab/131',
         )
-
-        v = DAVNumberValidator
-
-        for val in valid_data:
-            try:
-                v(val)
-            except ValidationError as e:  # pragma: no cover
-                self.fail('%s: %s' % (val, e))
-
-        for val in invalid_data:
-            try:
-                v(val)
-            except ValidationError:
-                pass
-            else:  # pragma: no cover
-                self.fail('%s: no ValidationError was raised' % val)
+        self.assertInvalid(self.validator, data)