Ticket #26142: 26142-test.diff

tests/model_formsets/tests.py

@@ -427 +427 @@
             '<Author: Walt Whitman>',
         ])
 
+    def test_max_num_prevent_instance_creation(self):
+        Author.objects.create(name='Charles Baudelaire')
+        AuthorFormSet = modelformset_factory(Author, fields="__all__", max_num=1, extra=0, validate_max=True)
+        data = {
+            'form-TOTAL_FORMS': '1',
+            'form-INITIAL_FORMS': '0', # Would be 1 normally, but pretend the user edited it.
+            'form-MAX_NUM_FORMS': '0',
+            'form-0-name': 'Walt Whitman',
+        }
+        formset = AuthorFormSet(data, queryset=Author.objects.all())
+        self.assertTrue(formset.is_valid())
+        formset.save()
+        self.assertQuerysetEqual(Author.objects.all(), [
+            '<Author: Charles Baudelaire>',
+            '<Author: Walt Whitman>',
+        ])
+
     def test_min_num(self):
         # Test the behavior of min_num with model formsets. It should be
         # added to extra.