Reorganized datetime db function tests.

tests/db_functions/datetime/test_now.py

@@ -0,0 +1,46 @@
+from datetime import datetime, timedelta
+
+from django.db.models.functions import Now
+from django.test import TestCase
+from django.utils import timezone
+
+from ..models import Article
+
+lorem_ipsum = """
+    Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod
+    tempor incididunt ut labore et dolore magna aliqua."""
+
+
+class NowTests(TestCase):
+
+    def test_basic(self):
+        a1 = Article.objects.create(
+            title='How to Django',
+            text=lorem_ipsum,
+            written=timezone.now(),
+        )
+        a2 = Article.objects.create(
+            title='How to Time Travel',
+            text=lorem_ipsum,
+            written=timezone.now(),
+        )
+        num_updated = Article.objects.filter(id=a1.id, published=None).update(published=Now())
+        self.assertEqual(num_updated, 1)
+        num_updated = Article.objects.filter(id=a1.id, published=None).update(published=Now())
+        self.assertEqual(num_updated, 0)
+        a1.refresh_from_db()
+        self.assertIsInstance(a1.published, datetime)
+        a2.published = Now() + timedelta(days=2)
+        a2.save()
+        a2.refresh_from_db()
+        self.assertIsInstance(a2.published, datetime)
+        self.assertQuerysetEqual(
+            Article.objects.filter(published__lte=Now()),
+            ['How to Django'],
+            lambda a: a.title
+        )
+        self.assertQuerysetEqual(
+            Article.objects.filter(published__gt=Now()),
+            ['How to Time Travel'],
+            lambda a: a.title
+        )