fix: render human-friendly datetime for such fields in version diff

still render the "raw" value but include human-friendly for convenience

tests/test_diffs.py

@@ -1,5 +1,14 @@
 # -*- coding: utf-8; -*-
 
+import datetime
+import re
+from unittest.mock import patch
+
+import sqlalchemy as sa
+from sqlalchemy import orm
+
+from wuttjamaican.util import get_timezone_by_name
+
 from wuttaweb import diffs as mod
 from wuttaweb.testing import WebTestCase, VersionWebTestCase
 
@@ -70,7 +79,7 @@ class TestVersionDiff(VersionWebTestCase):
             ["active", "person_uuid", "prevent_edit", "username", "uuid"],
         )
 
-    def test_render_version_value(self):
+    def test_render_version_value_with_objref(self):
         import sqlalchemy_continuum as continuum
 
         model = self.app.model
@@ -130,3 +139,91 @@ class TestVersionDiff(VersionWebTestCase):
         self.assertIn(str(person.uuid), html)
         self.assertIn("Fred Flintstone", html)
         self.assertEqual(diff.render_new_value("person_uuid"), "")
+
+    def test_render_version_value_with_datetime(self):
+        import sqlalchemy_continuum as continuum
+
+        tzlocal = get_timezone_by_name("America/Los_Angeles")
+        with patch.object(self.app, "get_timezone", return_value=tzlocal):
+
+            # make one person
+            model = self.app.model
+            person = model.Person(full_name="Fred Flintstone")
+            self.session.add(person)
+            self.session.commit()
+
+            # get its one version record
+            txncls = continuum.transaction_class(model.Person)
+            vercls = continuum.version_class(model.Person)
+            version = self.session.query(vercls).order_by(vercls.transaction_id).one()
+
+            # make a diff, but we have to mock some things up for the test
+            # coverage, since we don't currently have a versioned datetime
+            # field in the base model.
+            diff = self.make_diff(version)
+
+            mock_column = sa.Column("timestamp", sa.DateTime())
+            mock_property = orm.ColumnProperty(column=mock_column)
+
+            class MockMapper:
+                def __init__(self, mapper):
+                    self.mapper = mapper
+
+                def __getattr__(self, name):
+                    if hasattr(self.mapper, name):
+                        return getattr(self.mapper, name)
+                    raise AttributeError(f"attr not found: {name}")
+
+                def has_property(self, field):
+                    if field == "timestamp":
+                        return True
+                    return self.mapper.has_property(field)
+
+                def get_property(self, field):
+                    if field == "timestamp":
+                        return mock_property
+                    return self.mapper.get_property(field)
+
+            mock_mapper = MockMapper(diff.mapper)
+            with patch.object(diff, "mapper", new=mock_mapper):
+
+                # zone-aware local time
+                dt = datetime.datetime(2026, 3, 14, 14, 0, tzinfo=tzlocal)
+                html = diff.render_version_value(version, "timestamp", dt)
+                self.assertTrue(
+                    re.search(
+                        r'<span style="[^"]+"><span title="[^"]+">\d{4}-\d{2}-\d{2} \d{2}:\d{2}-\d{4}</span></span>',
+                        html,
+                    )
+                )
+                self.assertTrue(
+                    re.search(
+                        r'<span style="[^"]+"><span title="[^"]+">2026-03-14 14:00-0700</span></span>',
+                        html,
+                    )
+                )
+
+                # zone-naive (presumed UTC)
+                dt = datetime.datetime(2026, 3, 14, 21, 0)
+                html = diff.render_version_value(version, "timestamp", dt)
+                self.assertTrue(
+                    re.search(
+                        r'<span style="[^"]+"><span title="[^"]+">\d{4}-\d{2}-\d{2} \d{2}:\d{2}-\d{4}</span></span>',
+                        html,
+                    )
+                )
+                self.assertTrue(
+                    re.search(
+                        r'<span style="[^"]+"><span title="[^"]+">2026-03-14 14:00-0700</span></span>',
+                        html,
+                    )
+                )
+
+                # null
+                html = diff.render_version_value(version, "timestamp", None)
+                self.assertFalse(
+                    re.search(
+                        r'<span style="[^"]+"><span title="[^"]+">\d{4}-\d{2}-\d{2} \d{2}:\d{2}-\d{4}</span></span>',
+                        html,
+                    )
+                )