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django/tests/db_functions/comparison/test_coalesce.py
2022-02-07 20:37:05 +01:00

75 lines
2.9 KiB
Python

from django.db.models import Subquery, TextField
from django.db.models.functions import Coalesce, Lower
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 CoalesceTests(TestCase):
def test_basic(self):
Author.objects.create(name="John Smith", alias="smithj")
Author.objects.create(name="Rhonda")
authors = Author.objects.annotate(display_name=Coalesce("alias", "name"))
self.assertQuerysetEqual(
authors.order_by("name"), ["smithj", "Rhonda"], lambda a: a.display_name
)
def test_gt_two_expressions(self):
with self.assertRaisesMessage(
ValueError, "Coalesce must take at least two expressions"
):
Author.objects.annotate(display_name=Coalesce("alias"))
def test_mixed_values(self):
a1 = Author.objects.create(name="John Smith", alias="smithj")
a2 = Author.objects.create(name="Rhonda")
ar1 = Article.objects.create(
title="How to Django",
text=lorem_ipsum,
written=timezone.now(),
)
ar1.authors.add(a1)
ar1.authors.add(a2)
# mixed Text and Char
article = Article.objects.annotate(
headline=Coalesce("summary", "text", output_field=TextField()),
)
self.assertQuerysetEqual(
article.order_by("title"), [lorem_ipsum], lambda a: a.headline
)
# mixed Text and Char wrapped
article = Article.objects.annotate(
headline=Coalesce(
Lower("summary"), Lower("text"), output_field=TextField()
),
)
self.assertQuerysetEqual(
article.order_by("title"), [lorem_ipsum.lower()], lambda a: a.headline
)
def test_ordering(self):
Author.objects.create(name="John Smith", alias="smithj")
Author.objects.create(name="Rhonda")
authors = Author.objects.order_by(Coalesce("alias", "name"))
self.assertQuerysetEqual(authors, ["Rhonda", "John Smith"], lambda a: a.name)
authors = Author.objects.order_by(Coalesce("alias", "name").asc())
self.assertQuerysetEqual(authors, ["Rhonda", "John Smith"], lambda a: a.name)
authors = Author.objects.order_by(Coalesce("alias", "name").desc())
self.assertQuerysetEqual(authors, ["John Smith", "Rhonda"], lambda a: a.name)
def test_empty_queryset(self):
Author.objects.create(name="John Smith")
tests = [
Author.objects.none(),
Subquery(Author.objects.none()),
]
for empty_query in tests:
with self.subTest(empty_query.__class__.__name__):
qs = Author.objects.annotate(annotation=Coalesce(empty_query, 42))
self.assertEqual(qs.first().annotation, 42)