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			75 lines
		
	
	
		
			2.9 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			75 lines
		
	
	
		
			2.9 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
| from django.db.models import Subquery, TextField
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| from django.db.models.functions import Coalesce, Lower
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| from django.test import TestCase
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| from django.utils import timezone
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| 
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| from ..models import Article, Author
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| 
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| lorem_ipsum = """
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|     Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod
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|     tempor incididunt ut labore et dolore magna aliqua."""
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| 
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| 
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| class CoalesceTests(TestCase):
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|     def test_basic(self):
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|         Author.objects.create(name="John Smith", alias="smithj")
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|         Author.objects.create(name="Rhonda")
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|         authors = Author.objects.annotate(display_name=Coalesce("alias", "name"))
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|         self.assertQuerysetEqual(
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|             authors.order_by("name"), ["smithj", "Rhonda"], lambda a: a.display_name
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|         )
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| 
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|     def test_gt_two_expressions(self):
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|         with self.assertRaisesMessage(
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|             ValueError, "Coalesce must take at least two expressions"
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|         ):
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|             Author.objects.annotate(display_name=Coalesce("alias"))
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| 
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|     def test_mixed_values(self):
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|         a1 = Author.objects.create(name="John Smith", alias="smithj")
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|         a2 = Author.objects.create(name="Rhonda")
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|         ar1 = Article.objects.create(
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|             title="How to Django",
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|             text=lorem_ipsum,
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|             written=timezone.now(),
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|         )
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|         ar1.authors.add(a1)
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|         ar1.authors.add(a2)
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|         # mixed Text and Char
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|         article = Article.objects.annotate(
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|             headline=Coalesce("summary", "text", output_field=TextField()),
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|         )
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|         self.assertQuerysetEqual(
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|             article.order_by("title"), [lorem_ipsum], lambda a: a.headline
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|         )
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|         # mixed Text and Char wrapped
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|         article = Article.objects.annotate(
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|             headline=Coalesce(
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|                 Lower("summary"), Lower("text"), output_field=TextField()
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|             ),
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|         )
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|         self.assertQuerysetEqual(
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|             article.order_by("title"), [lorem_ipsum.lower()], lambda a: a.headline
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|         )
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| 
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|     def test_ordering(self):
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|         Author.objects.create(name="John Smith", alias="smithj")
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|         Author.objects.create(name="Rhonda")
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|         authors = Author.objects.order_by(Coalesce("alias", "name"))
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|         self.assertQuerysetEqual(authors, ["Rhonda", "John Smith"], lambda a: a.name)
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|         authors = Author.objects.order_by(Coalesce("alias", "name").asc())
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|         self.assertQuerysetEqual(authors, ["Rhonda", "John Smith"], lambda a: a.name)
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|         authors = Author.objects.order_by(Coalesce("alias", "name").desc())
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|         self.assertQuerysetEqual(authors, ["John Smith", "Rhonda"], lambda a: a.name)
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| 
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|     def test_empty_queryset(self):
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|         Author.objects.create(name="John Smith")
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|         tests = [
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|             Author.objects.none(),
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|             Subquery(Author.objects.none()),
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|         ]
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|         for empty_query in tests:
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|             with self.subTest(empty_query.__class__.__name__):
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|                 qs = Author.objects.annotate(annotation=Coalesce(empty_query, 42))
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|                 self.assertEqual(qs.first().annotation, 42)
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