UPD: more cool participant admin stuff.

dav_base/static/dav_base/css/local.css

@@ -140,4 +140,11 @@ thead input {
   content:"*";
   color: red;
 }
-*/
+*/
+
+/*
+ * Used to remove the space around link like buttons (<button class="btn btn-link no-padding">).
+ */
+.no-padding {
+    padding: 0px;
+}

dav_base/tests/test_validators.py

@@ -0,0 +1,37 @@
+from django.test import SimpleTestCase
+
+from .generic import ValidatorTestMixin
+
+from ..validators import DAVNumberValidator
+
+
+class DAVNumberValidatorTestCase(ValidatorTestMixin, SimpleTestCase):
+    validator = DAVNumberValidator
+
+    def test_valid_data(self):
+        data = (
+            '131/00/1',
+            '1',
+            '22',
+            '333',
+            '1/22/22',
+            '54321/54321/54321*54321',
+            '54321/54321/54321*54321*4321*4321',
+            '54321/54321/54321*54321*4321*4321*87654321',
+            '54321*54321',
+            '54321*54321*4321*4321',
+            '54321*54321*4321*4321*87654321',
+        )
+        self.assertValid(self.validator, data)
+
+    def test_invalid_data(self):
+        data = (
+            '131/00/',
+            '1/1/1',
+            '1/1',
+            'abc',
+            '131/00/abc',
+            'abc/00/131',
+            '131/ab/131',
+        )
+        self.assertInvalid(self.validator, data)

dav_base/validators.py

@@ -0,0 +1,13 @@
+# -*- coding: utf-8 -*-
+from django.core.validators import RegexValidator
+from django.utils.translation import ugettext_lazy as _
+
+
+DAVNumberValidator = RegexValidator(r'^'
+                                    r'([0-9]{1,10}/[0-9]{2,10}/)?'
+                                    r'[0-9]{1,10}'
+                                    r'(\*[0-9]{1,10})?'
+                                    r'(\*[0-9]{4}\*[0-9]{4})?'
+                                    r'([* ][0-9]{8})?'
+                                    r'$',
+                                    _(u'Ungültiges Format.'))