From 2ece405b6dbe8128bd80345da1922228536ac876 Mon Sep 17 00:00:00 2001
From: stumpylog <797416+stumpylog@users.noreply.github.com>
Date: Mon, 27 Jul 2026 15:24:41 -0700
Subject: [PATCH] test: add permission-filtering security regression suite for
 Document

---
 .../test_permission_filtering_security.py     | 121 ++++++++++++++++++
 1 file changed, 121 insertions(+)
 create mode 100644 src/documents/tests/test_permission_filtering_security.py

diff --git a/src/documents/tests/test_permission_filtering_security.py b/src/documents/tests/test_permission_filtering_security.py
new file mode 100644
index 000000000..b1704ece0
--- /dev/null
+++ b/src/documents/tests/test_permission_filtering_security.py
@@ -0,0 +1,121 @@
+from __future__ import annotations
+
+import pytest
+from django.contrib.auth.models import AnonymousUser
+from django.contrib.auth.models import Group
+from django.contrib.auth.models import User
+from guardian.shortcuts import assign_perm
+
+from documents.permissions import permitted_document_ids
+from documents.tests.factories import DocumentFactory
+
+
+def assert_visible_document_ids(actual_ids, *, expected_visible, expected_hidden):
+    actual_ids = set(actual_ids)
+    for doc_id in expected_visible:
+        assert doc_id in actual_ids, (
+            f"document {doc_id} should be visible but was hidden"
+        )
+    for doc_id in expected_hidden:
+        assert doc_id not in actual_ids, (
+            f"document {doc_id} leaked but should be hidden"
+        )
+
+
+@pytest.mark.django_db
+class TestPermittedDocumentIdsSecurity:
+    def test_owner_sees_own_document(self):
+        user = User.objects.create_user(username="alice")
+        stranger = User.objects.create_user(username="mallory")
+        owned = DocumentFactory(owner=user)
+        strangers_doc = DocumentFactory(owner=stranger)
+
+        visible = permitted_document_ids(user)
+
+        assert_visible_document_ids(
+            visible,
+            expected_visible=[owned.pk],
+            expected_hidden=[strangers_doc.pk],
+        )
+
+    def test_unowned_document_visible_to_everyone(self):
+        user = User.objects.create_user(username="alice")
+        unowned = DocumentFactory(owner=None)
+
+        assert_visible_document_ids(
+            permitted_document_ids(user),
+            expected_visible=[unowned.pk],
+            expected_hidden=[],
+        )
+
+    def test_explicit_user_permission_grants_visibility(self):
+        grantee = User.objects.create_user(username="alice")
+        stranger = User.objects.create_user(username="mallory")
+        owner = User.objects.create_user(username="owner")
+        shared = DocumentFactory(owner=owner)
+        not_shared = DocumentFactory(owner=owner)
+        assign_perm("view_document", grantee, shared)
+
+        assert_visible_document_ids(
+            permitted_document_ids(grantee),
+            expected_visible=[shared.pk],
+            expected_hidden=[not_shared.pk],
+        )
+        assert_visible_document_ids(
+            permitted_document_ids(stranger),
+            expected_visible=[],
+            expected_hidden=[shared.pk, not_shared.pk],
+        )
+
+    def test_explicit_group_permission_grants_visibility_to_members_only(self):
+        owner = User.objects.create_user(username="owner")
+        member = User.objects.create_user(username="member")
+        non_member = User.objects.create_user(username="non_member")
+        group = Group.objects.create(name="finance")
+        member.groups.add(group)
+        shared = DocumentFactory(owner=owner)
+        assign_perm("view_document", group, shared)
+
+        assert_visible_document_ids(
+            permitted_document_ids(member),
+            expected_visible=[shared.pk],
+            expected_hidden=[],
+        )
+        assert_visible_document_ids(
+            permitted_document_ids(non_member),
+            expected_visible=[],
+            expected_hidden=[shared.pk],
+        )
+
+    def test_soft_deleted_document_excluded_by_default(self):
+        owner = User.objects.create_user(username="owner")
+        doc = DocumentFactory(owner=owner)
+        doc.delete()  # soft delete
+
+        assert_visible_document_ids(
+            permitted_document_ids(owner),
+            expected_visible=[],
+            expected_hidden=[doc.pk],
+        )
+
+    def test_superuser_sees_everything_including_no_perm_documents(self):
+        superuser = User.objects.create_superuser(username="root")
+        owner = User.objects.create_user(username="owner")
+        doc = DocumentFactory(owner=owner)
+
+        assert_visible_document_ids(
+            permitted_document_ids(superuser),
+            expected_visible=[doc.pk],
+            expected_hidden=[],
+        )
+
+    def test_anonymous_user_sees_only_unowned_documents(self):
+        owner = User.objects.create_user(username="owner")
+        owned = DocumentFactory(owner=owner)
+        unowned = DocumentFactory(owner=None)
+
+        assert_visible_document_ids(
+            permitted_document_ids(AnonymousUser()),
+            expected_visible=[unowned.pk],
+            expected_hidden=[owned.pk],
+        )