| from django.db.models import Value as V |
| from django.db.models.functions import Lower, StrIndex, Substr, Upper |
| from django.test import TestCase |
|
|
| from ..models import Author |
|
|
|
|
| class SubstrTests(TestCase): |
| def test_basic(self): |
| Author.objects.create(name="John Smith", alias="smithj") |
| Author.objects.create(name="Rhonda") |
| authors = Author.objects.annotate(name_part=Substr("name", 5, 3)) |
| self.assertQuerySetEqual( |
| authors.order_by("name"), [" Sm", "da"], lambda a: a.name_part |
| ) |
| authors = Author.objects.annotate(name_part=Substr("name", 2)) |
| self.assertQuerySetEqual( |
| authors.order_by("name"), ["ohn Smith", "honda"], lambda a: a.name_part |
| ) |
| |
| Author.objects.filter(alias__isnull=True).update( |
| alias=Lower(Substr("name", 1, 5)), |
| ) |
| self.assertQuerySetEqual( |
| authors.order_by("name"), ["smithj", "rhond"], lambda a: a.alias |
| ) |
|
|
| def test_start(self): |
| Author.objects.create(name="John Smith", alias="smithj") |
| a = Author.objects.annotate( |
| name_part_1=Substr("name", 1), |
| name_part_2=Substr("name", 2), |
| ).get(alias="smithj") |
|
|
| self.assertEqual(a.name_part_1[1:], a.name_part_2) |
|
|
| def test_pos_gt_zero(self): |
| with self.assertRaisesMessage(ValueError, "'pos' must be greater than 0"): |
| Author.objects.annotate(raises=Substr("name", 0)) |
|
|
| def test_expressions(self): |
| Author.objects.create(name="John Smith", alias="smithj") |
| Author.objects.create(name="Rhonda") |
| substr = Substr(Upper("name"), StrIndex("name", V("h")), 5) |
| authors = Author.objects.annotate(name_part=substr) |
| self.assertQuerySetEqual( |
| authors.order_by("name"), ["HN SM", "HONDA"], lambda a: a.name_part |
| ) |
|
|
