Fixed #20347 -- Allowed customizing the maximum number of instantiated forms in formsets.

Co-authored-by: ethurgood <ethurgood@gmail.com>

1 files changed, 49 insertions, 0 deletions

diff --git a/tests/forms_tests/tests/test_formsets.py b/tests/forms_tests/tests/test_formsets.py
index 117b50fa7c..e44b347802 100644
--- a/tests/forms_tests/tests/test_formsets.py
+++ b/tests/forms_tests/tests/test_formsets.py
@@ -892,6 +892,55 @@ class FormsFormsetTestCase(SimpleTestCase):
         )
         self.assertEqual(formset.absolute_max, 2000)
 
+    def test_absolute_max(self):
+        data = {
+            'form-TOTAL_FORMS': '2001',
+            'form-INITIAL_FORMS': '0',
+            'form-MAX_NUM_FORMS': '0',
+        }
+        AbsoluteMaxFavoriteDrinksFormSet = formset_factory(
+            FavoriteDrinkForm,
+            absolute_max=3000,
+        )
+        formset = AbsoluteMaxFavoriteDrinksFormSet(data=data)
+        self.assertIs(formset.is_valid(), True)
+        self.assertEqual(len(formset.forms), 2001)
+        # absolute_max provides a hard limit.
+        data['form-TOTAL_FORMS'] = '3001'
+        formset = AbsoluteMaxFavoriteDrinksFormSet(data=data)
+        self.assertIs(formset.is_valid(), False)
+        self.assertEqual(len(formset.forms), 3000)
+        self.assertEqual(
+            formset.non_form_errors(),
+            ['Please submit 1000 or fewer forms.'],
+        )
+
+    def test_absolute_max_with_max_num(self):
+        data = {
+            'form-TOTAL_FORMS': '1001',
+            'form-INITIAL_FORMS': '0',
+            'form-MAX_NUM_FORMS': '0',
+        }
+        LimitedFavoriteDrinksFormSet = formset_factory(
+            FavoriteDrinkForm,
+            max_num=30,
+            absolute_max=1000,
+        )
+        formset = LimitedFavoriteDrinksFormSet(data=data)
+        self.assertIs(formset.is_valid(), False)
+        self.assertEqual(len(formset.forms), 1000)
+        self.assertEqual(
+            formset.non_form_errors(),
+            ['Please submit 30 or fewer forms.'],
+        )
+
+    def test_absolute_max_invalid(self):
+        msg = "'absolute_max' must be greater or equal to 'max_num'."
+        for max_num in [None, 31]:
+            with self.subTest(max_num=max_num):
+                with self.assertRaisesMessage(ValueError, msg):
+                    formset_factory(FavoriteDrinkForm, max_num=max_num, absolute_max=30)
+
     def test_more_initial_form_result_in_one(self):
         """
         One form from initial and extra=3 with max_num=2 results in the one