Refs #20347 -- Added test for formset_factory()'s absolute_max default.

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

tests/forms_tests/tests/test_formsets.py

@@ -877,6 +877,21 @@ class FormsFormsetTestCase(SimpleTestCase):
 <td><input id="id_form-2-name" name="form-2-name" type="text" value="Jack and Coke"></td></tr>"""
         )
 
+    def test_default_absolute_max(self):
+        # absolute_max defaults to 2 * DEFAULT_MAX_NUM if max_num is None.
+        data = {
+            'form-TOTAL_FORMS': 2001,
+            'form-INITIAL_FORMS': '0',
+            'form-MAX_NUM_FORMS': '0',
+        }
+        formset = FavoriteDrinksFormSet(data=data)
+        self.assertIs(formset.is_valid(), False)
+        self.assertEqual(
+            formset.non_form_errors(),
+            ['Please submit 1000 or fewer forms.'],
+        )
+        self.assertEqual(formset.absolute_max, 2000)
+
     def test_more_initial_form_result_in_one(self):
         """
         One form from initial and extra=3 with max_num=2 results in the one