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41 lines
1.4 KiB
Python
41 lines
1.4 KiB
Python
from unittest import skipUnless
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from django.db import connection
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from django.db.models import Value
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from django.db.models.functions import NullIf
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from django.test import TestCase
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from ..models import Author
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class NullIfTests(TestCase):
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@classmethod
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def setUpTestData(cls):
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Author.objects.create(name='John Smith', alias='smithj')
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Author.objects.create(name='Rhonda', alias='Rhonda')
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def test_basic(self):
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authors = Author.objects.annotate(nullif=NullIf('alias', 'name')).values_list('nullif')
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self.assertSequenceEqual(
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authors, [
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('smithj',),
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('' if connection.features.interprets_empty_strings_as_nulls else None,)
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]
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)
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def test_null_argument(self):
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authors = Author.objects.annotate(nullif=NullIf('name', Value(None))).values_list('nullif')
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self.assertSequenceEqual(authors, [('John Smith',), ('Rhonda',)])
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def test_too_few_args(self):
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msg = "'NullIf' takes exactly 2 arguments (1 given)"
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with self.assertRaisesMessage(TypeError, msg):
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NullIf('name')
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@skipUnless(connection.vendor == 'oracle', 'Oracle specific test for NULL-literal')
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def test_null_literal(self):
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msg = 'Oracle does not allow Value(None) for expression1.'
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with self.assertRaisesMessage(ValueError, msg):
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list(Author.objects.annotate(nullif=NullIf(Value(None), 'name')).values_list('nullif'))
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