Bugfix: add missing max_length check on TagSerializer

Issue: CORE-4S2

Progress on comses#377

django/core/serializers.py

@@ -34,7 +34,7 @@ def save(self, **kwargs):
 
 
 class TagSerializer(serializers.ModelSerializer):
-    name = serializers.CharField()  # disable uniqueness check so TagListSerializer will validate properly
+    name = serializers.CharField(max_length=Tag._meta.get_field('name').max_length)  # disable uniqueness check so TagListSerializer will validate properly
 
     class Meta:
         model = Tag

django/core/tests/test_serializers.py

@@ -0,0 +1,14 @@
+from django.test import TestCase
+from taggit.models import Tag
+
+from core.serializers import TagSerializer
+
+
+class TagSerializerTestCase(TestCase):
+    def test_name_max_length_check_respected(self):
+        too_long = Tag._meta.get_field('name').max_length + 1
+        name_too_long = TagSerializer(data={'name': 'a'*too_long})
+        self.assertFalse(name_too_long.is_valid())
+
+        valid_name = TagSerializer(data={'name': 'fishing'})
+        self.assertTrue(valid_name.is_valid())