102 lines
3.8 KiB
Python
102 lines
3.8 KiB
Python
from datetime import datetime, timedelta
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from decimal import Decimal
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from unittest import skipUnless
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from django.db import connection
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from django.db.models.expressions import RawSQL
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from django.db.models.functions import Coalesce, Greatest
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from django.test import TestCase, skipIfDBFeature, skipUnlessDBFeature
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from django.utils import timezone
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from ..models import Article, Author, DecimalModel, Fan
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class GreatestTests(TestCase):
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def test_basic(self):
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now = timezone.now()
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before = now - timedelta(hours=1)
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Article.objects.create(
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title="Testing with Django", written=before, published=now
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)
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articles = Article.objects.annotate(
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last_updated=Greatest("written", "published")
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)
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self.assertEqual(articles.first().last_updated, now)
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@skipUnlessDBFeature("greatest_least_ignores_nulls")
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def test_ignores_null(self):
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now = timezone.now()
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Article.objects.create(title="Testing with Django", written=now)
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articles = Article.objects.annotate(
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last_updated=Greatest("written", "published")
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)
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self.assertEqual(articles.first().last_updated, now)
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@skipIfDBFeature("greatest_least_ignores_nulls")
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def test_propagates_null(self):
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Article.objects.create(title="Testing with Django", written=timezone.now())
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articles = Article.objects.annotate(
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last_updated=Greatest("written", "published")
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)
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self.assertIsNone(articles.first().last_updated)
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def test_coalesce_workaround(self):
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past = datetime(1900, 1, 1)
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now = timezone.now()
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Article.objects.create(title="Testing with Django", written=now)
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articles = Article.objects.annotate(
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last_updated=Greatest(
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Coalesce("written", past),
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Coalesce("published", past),
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),
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)
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self.assertEqual(articles.first().last_updated, now)
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@skipUnless(connection.vendor == "mysql", "MySQL-specific workaround")
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def test_coalesce_workaround_mysql(self):
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past = datetime(1900, 1, 1)
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now = timezone.now()
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Article.objects.create(title="Testing with Django", written=now)
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past_sql = RawSQL("cast(%s as datetime)", (past,))
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articles = Article.objects.annotate(
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last_updated=Greatest(
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Coalesce("written", past_sql),
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Coalesce("published", past_sql),
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),
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)
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self.assertEqual(articles.first().last_updated, now)
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def test_all_null(self):
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Article.objects.create(title="Testing with Django", written=timezone.now())
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articles = Article.objects.annotate(
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last_updated=Greatest("published", "updated")
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)
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self.assertIsNone(articles.first().last_updated)
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def test_one_expressions(self):
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with self.assertRaisesMessage(
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ValueError, "Greatest must take at least two expressions"
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):
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Greatest("written")
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def test_related_field(self):
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author = Author.objects.create(name="John Smith", age=45)
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Fan.objects.create(name="Margaret", age=50, author=author)
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authors = Author.objects.annotate(highest_age=Greatest("age", "fans__age"))
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self.assertEqual(authors.first().highest_age, 50)
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def test_update(self):
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author = Author.objects.create(name="James Smith", goes_by="Jim")
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Author.objects.update(alias=Greatest("name", "goes_by"))
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author.refresh_from_db()
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self.assertEqual(author.alias, "Jim")
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def test_decimal_filter(self):
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obj = DecimalModel.objects.create(n1=Decimal("1.1"), n2=Decimal("1.2"))
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self.assertCountEqual(
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DecimalModel.objects.annotate(
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greatest=Greatest("n1", "n2"),
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).filter(greatest=Decimal("1.2")),
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[obj],
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)
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