from datetime import datetime from django.test import TestCase from .models import Article, IndexErrorArticle, Person class EarliestOrLatestTests(TestCase): """Tests for the earliest() and latest() objects methods""" @classmethod def setUpClass(cls): super().setUpClass() cls._article_get_latest_by = Article._meta.get_latest_by def tearDown(self): Article._meta.get_latest_by = self._article_get_latest_by def test_earliest(self): # Because no Articles exist yet, earliest() raises ArticleDoesNotExist. with self.assertRaises(Article.DoesNotExist): Article.objects.earliest() a1 = Article.objects.create( headline="Article 1", pub_date=datetime(2005, 7, 26), expire_date=datetime(2005, 9, 1) ) a2 = Article.objects.create( headline="Article 2", pub_date=datetime(2005, 7, 27), expire_date=datetime(2005, 7, 28) ) a3 = Article.objects.create( headline="Article 3", pub_date=datetime(2005, 7, 28), expire_date=datetime(2005, 8, 27) ) a4 = Article.objects.create( headline="Article 4", pub_date=datetime(2005, 7, 28), expire_date=datetime(2005, 7, 30) ) # Get the earliest Article. self.assertEqual(Article.objects.earliest(), a1) # Get the earliest Article that matches certain filters. self.assertEqual( Article.objects.filter(pub_date__gt=datetime(2005, 7, 26)).earliest(), a2 ) # Pass a custom field name to earliest() to change the field that's used # to determine the earliest object. self.assertEqual(Article.objects.earliest('expire_date'), a2) self.assertEqual(Article.objects.filter( pub_date__gt=datetime(2005, 7, 26)).earliest('expire_date'), a2) # earliest() overrides any other ordering specified on the query. # Refs #11283. self.assertEqual(Article.objects.order_by('id').earliest(), a1) # Error is raised if the user forgot to add a get_latest_by # in the Model.Meta Article.objects.model._meta.get_latest_by = None with self.assertRaisesMessage( ValueError, "earliest() and latest() require either fields as positional " "arguments or 'get_latest_by' in the model's Meta." ): Article.objects.earliest() # Earliest publication date, earliest expire date. self.assertEqual( Article.objects.filter(pub_date=datetime(2005, 7, 28)).earliest('pub_date', 'expire_date'), a4, ) # Earliest publication date, latest expire date. self.assertEqual( Article.objects.filter(pub_date=datetime(2005, 7, 28)).earliest('pub_date', '-expire_date'), a3, ) # Meta.get_latest_by may be a tuple. Article.objects.model._meta.get_latest_by = ('pub_date', 'expire_date') self.assertEqual(Article.objects.filter(pub_date=datetime(2005, 7, 28)).earliest(), a4) def test_latest(self): # Because no Articles exist yet, latest() raises ArticleDoesNotExist. with self.assertRaises(Article.DoesNotExist): Article.objects.latest() a1 = Article.objects.create( headline="Article 1", pub_date=datetime(2005, 7, 26), expire_date=datetime(2005, 9, 1) ) a2 = Article.objects.create( headline="Article 2", pub_date=datetime(2005, 7, 27), expire_date=datetime(2005, 7, 28) ) a3 = Article.objects.create( headline="Article 3", pub_date=datetime(2005, 7, 27), expire_date=datetime(2005, 8, 27) ) a4 = Article.objects.create( headline="Article 4", pub_date=datetime(2005, 7, 28), expire_date=datetime(2005, 7, 30) ) # Get the latest Article. self.assertEqual(Article.objects.latest(), a4) # Get the latest Article that matches certain filters. self.assertEqual( Article.objects.filter(pub_date__lt=datetime(2005, 7, 27)).latest(), a1 ) # Pass a custom field name to latest() to change the field that's used # to determine the latest object. self.assertEqual(Article.objects.latest('expire_date'), a1) self.assertEqual( Article.objects.filter(pub_date__gt=datetime(2005, 7, 26)).latest('expire_date'), a3, ) # latest() overrides any other ordering specified on the query (#11283). self.assertEqual(Article.objects.order_by('id').latest(), a4) # Error is raised if get_latest_by isn't in Model.Meta. Article.objects.model._meta.get_latest_by = None with self.assertRaisesMessage( ValueError, "earliest() and latest() require either fields as positional " "arguments or 'get_latest_by' in the model's Meta." ): Article.objects.latest() # Latest publication date, latest expire date. self.assertEqual(Article.objects.filter(pub_date=datetime(2005, 7, 27)).latest('pub_date', 'expire_date'), a3) # Latest publication date, earliest expire date. self.assertEqual( Article.objects.filter(pub_date=datetime(2005, 7, 27)).latest('pub_date', '-expire_date'), a2, ) # Meta.get_latest_by may be a tuple. Article.objects.model._meta.get_latest_by = ('pub_date', 'expire_date') self.assertEqual(Article.objects.filter(pub_date=datetime(2005, 7, 27)).latest(), a3) def test_latest_manual(self): # You can still use latest() with a model that doesn't have # "get_latest_by" set -- just pass in the field name manually. Person.objects.create(name="Ralph", birthday=datetime(1950, 1, 1)) p2 = Person.objects.create(name="Stephanie", birthday=datetime(1960, 2, 3)) msg = ( "earliest() and latest() require either fields as positional arguments " "or 'get_latest_by' in the model's Meta." ) with self.assertRaisesMessage(ValueError, msg): Person.objects.latest() self.assertEqual(Person.objects.latest("birthday"), p2) class TestFirstLast(TestCase): def test_first(self): p1 = Person.objects.create(name="Bob", birthday=datetime(1950, 1, 1)) p2 = Person.objects.create(name="Alice", birthday=datetime(1961, 2, 3)) self.assertEqual(Person.objects.first(), p1) self.assertEqual(Person.objects.order_by('name').first(), p2) self.assertEqual(Person.objects.filter(birthday__lte=datetime(1955, 1, 1)).first(), p1) self.assertIsNone(Person.objects.filter(birthday__lte=datetime(1940, 1, 1)).first()) def test_last(self): p1 = Person.objects.create(name="Alice", birthday=datetime(1950, 1, 1)) p2 = Person.objects.create(name="Bob", birthday=datetime(1960, 2, 3)) # Note: by default PK ordering. self.assertEqual(Person.objects.last(), p2) self.assertEqual(Person.objects.order_by('-name').last(), p1) self.assertEqual(Person.objects.filter(birthday__lte=datetime(1955, 1, 1)).last(), p1) self.assertIsNone(Person.objects.filter(birthday__lte=datetime(1940, 1, 1)).last()) def test_index_error_not_suppressed(self): """ #23555 -- Unexpected IndexError exceptions in QuerySet iteration shouldn't be suppressed. """ def check(): # We know that we've broken the __iter__ method, so the queryset # should always raise an exception. with self.assertRaises(IndexError): IndexErrorArticle.objects.all()[:10:2] with self.assertRaises(IndexError): IndexErrorArticle.objects.all().first() with self.assertRaises(IndexError): IndexErrorArticle.objects.all().last() check() # And it does not matter if there are any records in the DB. IndexErrorArticle.objects.create( headline="Article 1", pub_date=datetime(2005, 7, 26), expire_date=datetime(2005, 9, 1) ) check()