fix: add render_date(), render_datetime() methods for app handler

src/wuttjamaican/app.py

@@ -668,6 +668,51 @@ class AppHandler:
 
         return False
 
+    ##############################
+    # common value renderers
+    ##############################
+
+    display_format_date = '%Y-%m-%d'
+    """
+    Format string to use when displaying :class:`python:datetime.date`
+    objects.  See also :meth:`render_date()`.
+    """
+
+    display_format_datetime = '%Y-%m-%d %H:%M%z'
+    """
+    Format string to use when displaying
+    :class:`python:datetime.datetime` objects.  See also
+    :meth:`render_datetime()`.
+    """
+
+    def render_date(self, value):
+        """
+        Return a human-friendly display string for the given date.
+
+        Uses :attr:`display_format_date` to render the value.
+
+        :param value: A :class:`python:datetime.date` instance (or
+           ``None``).
+
+        :returns: Display string, or ``None``.
+        """
+        if value is not None:
+            return value.strftime(self.display_format_date)
+
+    def render_datetime(self, value):
+        """
+        Return a human-friendly display string for the given datetime.
+
+        Uses :attr:`display_format_datetime` to render the value.
+
+        :param value: A :class:`python:datetime.datetime` instance (or
+           ``None``).
+
+        :returns: Display string, or ``None``.
+        """
+        if value is not None:
+            return value.strftime(self.display_format_datetime)
+
     ##############################
     # getters for other handlers
     ##############################

tests/test_app.py

@@ -1,5 +1,6 @@
 # -*- coding: utf-8; -*-
 
+import datetime
 import os
 import shutil
 import sys
@@ -421,6 +422,18 @@ app_title = WuttaTest
         session = self.app.get_session(user)
         self.assertIs(session, mysession)
 
+    def test_render_date(self):
+        self.assertIsNone(self.app.render_date(None))
+
+        dt = datetime.date(2024, 12, 11)
+        self.assertEqual(self.app.render_date(dt), '2024-12-11')
+
+    def test_render_datetime(self):
+        self.assertIsNone(self.app.render_datetime(None))
+
+        dt = datetime.datetime(2024, 12, 11, 8, 30, tzinfo=datetime.timezone.utc)
+        self.assertEqual(self.app.render_datetime(dt), '2024-12-11 08:30+0000')
+
     def test_get_person(self):
         people = self.app.get_people_handler()
         with patch.object(people, 'get_person') as get_person: