Fix: handle created change with api version increment, use created only on frontend, deprecate created_date (#9962)

src/documents/tests/test_api_documents.py

@@ -171,6 +171,38 @@ class TestDocumentApi(DirectoriesMixin, DocumentConsumeDelayMixin, APITestCase):
         results = response.data["results"]
         self.assertEqual(len(results[0]), 0)
 
+    def test_document_legacy_created_format(self):
+        """
+        GIVEN:
+            - Existing document
+        WHEN:
+            - Document is requested with api version ≥ 9
+            - Document is requested with api version < 9
+        THEN:
+            - Document created field is returned as date
+            - Document created field is returned as datetime
+        """
+        doc = Document.objects.create(
+            title="none",
+            checksum="123",
+            mime_type="application/pdf",
+            created=date(2023, 1, 1),
+        )
+
+        response = self.client.get(
+            f"/api/documents/{doc.pk}/",
+            headers={"Accept": "application/json; version=8"},
+        )
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        self.assertRegex(response.data["created"], r"^2023-01-01T00:00:00.*$")
+
+        response = self.client.get(
+            f"/api/documents/{doc.pk}/",
+            headers={"Accept": "application/json; version=9"},
+        )
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        self.assertEqual(response.data["created"], "2023-01-01")
+
     def test_document_update_with_created_date(self):
         """
         GIVEN: