django/tests/db_functions/text/test_concat.py

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2018-08-16 07:45:11 +08:00
from unittest import skipUnless
from django.db import connection
from django.db.models import CharField, TextField, Value as V
from django.db.models.functions import Concat, ConcatPair, Upper
from django.test import TestCase
from django.utils import timezone
from ..models import Article, Author
lorem_ipsum = """
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod
tempor incididunt ut labore et dolore magna aliqua."""
class ConcatTests(TestCase):
def test_basic(self):
Author.objects.create(name='Jayden')
Author.objects.create(name='John Smith', alias='smithj', goes_by='John')
Author.objects.create(name='Margaret', goes_by='Maggie')
Author.objects.create(name='Rhonda', alias='adnohR')
authors = Author.objects.annotate(joined=Concat('alias', 'goes_by'))
self.assertQuerysetEqual(
authors.order_by('name'), [
'',
'smithjJohn',
'Maggie',
'adnohR',
],
lambda a: a.joined
)
def test_gt_two_expressions(self):
with self.assertRaisesMessage(ValueError, 'Concat must take at least two expressions'):
Author.objects.annotate(joined=Concat('alias'))
def test_many(self):
Author.objects.create(name='Jayden')
Author.objects.create(name='John Smith', alias='smithj', goes_by='John')
Author.objects.create(name='Margaret', goes_by='Maggie')
Author.objects.create(name='Rhonda', alias='adnohR')
authors = Author.objects.annotate(
joined=Concat('name', V(' ('), 'goes_by', V(')'), output_field=CharField()),
)
self.assertQuerysetEqual(
authors.order_by('name'), [
'Jayden ()',
'John Smith (John)',
'Margaret (Maggie)',
'Rhonda ()',
],
lambda a: a.joined
)
def test_mixed_char_text(self):
Article.objects.create(title='The Title', text=lorem_ipsum, written=timezone.now())
article = Article.objects.annotate(
title_text=Concat('title', V(' - '), 'text', output_field=TextField()),
).get(title='The Title')
self.assertEqual(article.title + ' - ' + article.text, article.title_text)
# Wrap the concat in something else to ensure that text is returned
# rather than bytes.
article = Article.objects.annotate(
title_text=Upper(Concat('title', V(' - '), 'text', output_field=TextField())),
).get(title='The Title')
expected = article.title + ' - ' + article.text
self.assertEqual(expected.upper(), article.title_text)
@skipUnless(connection.vendor == 'sqlite', "sqlite specific implementation detail.")
def test_coalesce_idempotent(self):
pair = ConcatPair(V('a'), V('b'))
# Check nodes counts
self.assertEqual(len(list(pair.flatten())), 3)
self.assertEqual(len(list(pair.coalesce().flatten())), 7) # + 2 Coalesce + 2 Value()
self.assertEqual(len(list(pair.flatten())), 3)
def test_sql_generation_idempotency(self):
qs = Article.objects.annotate(description=Concat('title', V(': '), 'summary'))
# Multiple compilations should not alter the generated query.
self.assertEqual(str(qs.query), str(qs.all().query))