[1.7.x] Fixed #22537 -- Add tests and improved docs for field subclass with choices.

Backport of 7fd1b35ed7 from master

1 files changed, 12 insertions, 2 deletions

diff --git a/tests/field_subclassing/tests.py b/tests/field_subclassing/tests.py
index 5f1dbac8a3..5c695a455c 100644
--- a/tests/field_subclassing/tests.py
+++ b/tests/field_subclassing/tests.py
@@ -2,12 +2,12 @@ from __future__ import unicode_literals
 
 import inspect
 
-from django.core import serializers
+from django.core import exceptions, serializers
 from django.db import connection
 from django.test import TestCase
 
 from .fields import Small, CustomTypedField
-from .models import DataModel, MyModel, OtherModel
+from .models import ChoicesModel, DataModel, MyModel, OtherModel
 
 
 class CustomField(TestCase):
@@ -106,6 +106,16 @@ class CustomField(TestCase):
         self.assertIn('__module__', data)
         self.assertEqual(data['__module__'], 'field_subclassing.models')
 
+    def test_validation_of_choices_for_custom_field(self):
+        # a valid choice
+        o = ChoicesModel.objects.create(data=Small('a', 'b'))
+        o.full_clean()
+
+        # an invalid choice
+        o = ChoicesModel.objects.create(data=Small('d', 'e'))
+        with self.assertRaises(exceptions.ValidationError):
+            o.full_clean()
+
 
 class TestDbType(TestCase):