4 files changed, 90 insertions, 5 deletions
diff --git a/tests/admin_inlines/admin.py b/tests/admin_inlines/admin.py
index dbb74991dc..4ab00b1df6 100644
--- a/tests/admin_inlines/admin.py
+++ b/tests/admin_inlines/admin.py
@@ -296,6 +296,7 @@ class PollAdmin(admin.ModelAdmin):
 class ChapterInline(admin.TabularInline):
     model = Chapter
     readonly_fields = ["call_me"]
+    delete_confirmation_max_display = 3
 
     def call_me(self, obj):
         return "Callable in ChapterInline"
diff --git a/tests/admin_inlines/models.py b/tests/admin_inlines/models.py
index ea5ba78656..3c2758705c 100644
--- a/tests/admin_inlines/models.py
+++ b/tests/admin_inlines/models.py
@@ -247,9 +247,7 @@ class Chapter(models.Model):
 
 
 class FootNote(models.Model):
-    """
-    Model added for ticket 19838
-    """
+    """Model for models.PROTECT."""
 
     chapter = models.ForeignKey(Chapter, models.PROTECT)
     note = models.CharField(max_length=40)
diff --git a/tests/admin_inlines/tests.py b/tests/admin_inlines/tests.py
index eda7c91310..a2814a8d46 100644
--- a/tests/admin_inlines/tests.py
+++ b/tests/admin_inlines/tests.py
@@ -830,6 +830,76 @@ class TestInline(TestDataMixin, TestCase):
         parent.refresh_from_db()
         self.assertIs(parent.show_inlines, True)
 
+    def test_delete_protected_message_limits_number_of_objects_displayed(self):
+        # admin limits the number of displayed objects to 2, so we create
+        # 5 footnotes.
+        novel = Novel.objects.create()
+        chapter = Chapter.objects.create(novel=novel)
+        footnotes = [FootNote(chapter=chapter) for i in range(5)]
+        FootNote.objects.bulk_create(footnotes)
+
+        response = self.client.post(
+            reverse("admin:admin_inlines_novel_change", args=(novel.pk,)),
+            data={
+                "show_inlines": "on",
+                "chapter_set-TOTAL_FORMS": "1",
+                "chapter_set-INITIAL_FORMS": "1",
+                "chapter_set-MAX_NUM_FORMS": "1000",
+                "chapter_set-MIN_NUM_FORMS": "0",
+                "chapter_set-0-id": chapter.id,
+                "chapter_set-0-name": chapter.name,
+                "chapter_set-0-novel": novel.id,
+                "chapter_set-0-DELETE": "on",
+            },
+        )
+        self.assertEqual(response.status_code, 200)
+        inline_formset = response.context_data["inline_admin_formsets"][0]
+        self.assertEqual(1, len(inline_formset.non_form_errors()))
+        error_message = inline_formset.non_form_errors()[0]
+        self.assertTrue(
+            error_message.startswith(
+                f"Deleting chapter Chapter object ({chapter.pk}) would "
+                "require deleting the following protected related objects:"
+            ),
+            error_message,
+        )
+        self.assertEqual(error_message.count("FootNote"), 3, error_message)
+        self.assertTrue(error_message.endswith("…and 2 more objects."), error_message)
+
+    def test_delete_protected_message_does_not_limit_small_amount_of_objects(self):
+        novel = Novel.objects.create()
+        chapter = Chapter.objects.create(novel=novel)
+        footnotes = [FootNote(chapter=chapter) for i in range(3)]
+        FootNote.objects.bulk_create(footnotes)
+
+        response = self.client.post(
+            reverse("admin:admin_inlines_novel_change", args=(novel.pk,)),
+            data={
+                "show_inlines": "on",
+                "chapter_set-TOTAL_FORMS": "1",
+                "chapter_set-INITIAL_FORMS": "1",
+                "chapter_set-MAX_NUM_FORMS": "1000",
+                "chapter_set-MIN_NUM_FORMS": "0",
+                "chapter_set-0-id": chapter.id,
+                "chapter_set-0-name": chapter.name,
+                "chapter_set-0-novel": novel.id,
+                "chapter_set-0-DELETE": "on",
+            },
+        )
+        self.assertEqual(response.status_code, 200)
+        inline_formset = response.context_data["inline_admin_formsets"][0]
+        self.assertEqual(1, len(inline_formset.non_form_errors()))
+        error_message = inline_formset.non_form_errors()[0]
+        self.assertTrue(
+            error_message.startswith(
+                f"Deleting chapter Chapter object ({chapter.pk}) would require "
+                "deleting the following protected related objects:"
+            ),
+            error_message,
+        )
+        self.assertEqual(error_message.count("FootNote object"), 3)
+        self.assertNotIn("more", error_message)
+
 
 @override_settings(ROOT_URLCONF="admin_inlines.urls")
 class TestInlineMedia(TestDataMixin, TestCase):
diff --git a/tests/modeladmin/test_checks.py b/tests/modeladmin/test_checks.py
index bcac262d69..40777d1458 100644
--- a/tests/modeladmin/test_checks.py
+++ b/tests/modeladmin/test_checks.py
@@ -1033,7 +1033,7 @@ class DeleteConfirmationMaxObjectsCheckTests(CheckTestCase):
                 "'delete_confirmation_max_display'"
                 " must be a non-negative integer or None."
             ),
-            "admin.E131",
+            "admin.E041",
         )
 
     def test_negative_integer(self):
@@ -1048,7 +1048,7 @@ class DeleteConfirmationMaxObjectsCheckTests(CheckTestCase):
                 "'delete_confirmation_max_display'"
                 " must be a non-negative integer or None."
             ),
-            "admin.E131",
+            "admin.E041",
         )
 
     def test_valid_case(self):
@@ -1063,6 +1063,22 @@ class DeleteConfirmationMaxObjectsCheckTests(CheckTestCase):
 
         self.assertIsValid(TestModelAdmin, ValidationTestModel)
 
+    def test_inline_not_integer(self):
+        class TestInlineModelAdmin(TabularInline):
+            delete_confirmation_max_display = "goodbye"
+            model = ValidationTestInlineModel
+
+        self.assertIsInvalid(
+            TestInlineModelAdmin,
+            ValidationTestModel,
+            (
+                "The value of "
+                "'delete_confirmation_max_display'"
+                " must be a non-negative integer or None."
+            ),
+            "admin.E041",
+        )
+
 
 class SearchFieldsCheckTests(CheckTestCase):
     def test_not_iterable(self):