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