Fixed #29658 -- Registered model lookups in tests with a context manager.

tests/db_functions/text/test_chr.py

@@ -1,6 +1,7 @@
 from django.db.models import IntegerField
 from django.db.models.functions import Chr, Left, Ord
 from django.test import TestCase
+from django.test.utils import register_lookup
 
 from ..models import Author
 
@@ -23,10 +24,7 @@ class ChrTests(TestCase):
         self.assertCountEqual(authors.exclude(first_initial=Chr(ord('É'))), [self.john, self.rhonda])
 
     def test_transform(self):
-        try:
-            IntegerField.register_lookup(Chr)
+        with register_lookup(IntegerField, Chr):
             authors = Author.objects.annotate(name_code_point=Ord('name'))
             self.assertCountEqual(authors.filter(name_code_point__chr=Chr(ord('J'))), [self.john])
             self.assertCountEqual(authors.exclude(name_code_point__chr=Chr(ord('J'))), [self.elena, self.rhonda])
-        finally:
-            IntegerField._unregister_lookup(Chr)

tests/db_functions/text/test_length.py

@@ -1,6 +1,7 @@
 from django.db.models import CharField
 from django.db.models.functions import Length
 from django.test import TestCase
+from django.test.utils import register_lookup
 
 from ..models import Author
 
@@ -35,8 +36,7 @@ class LengthTests(TestCase):
         )
 
     def test_transform(self):
-        try:
-            CharField.register_lookup(Length)
+        with register_lookup(CharField, Length):
             Author.objects.create(name='John Smith', alias='smithj')
             Author.objects.create(name='Rhonda')
             authors = Author.objects.filter(name__length__gt=7)
@@ -44,5 +44,3 @@ class LengthTests(TestCase):
                 authors.order_by('name'), ['John Smith'],
                 lambda a: a.name
             )
-        finally:
-            CharField._unregister_lookup(Length)

tests/db_functions/text/test_lower.py

@@ -1,6 +1,7 @@
 from django.db.models import CharField
 from django.db.models.functions import Lower
 from django.test import TestCase
+from django.test.utils import register_lookup
 
 from ..models import Author
 
@@ -29,8 +30,7 @@ class LowerTests(TestCase):
             Author.objects.update(name=Lower('name', 'name'))
 
     def test_transform(self):
-        try:
-            CharField.register_lookup(Lower)
+        with register_lookup(CharField, Lower):
             Author.objects.create(name='John Smith', alias='smithj')
             Author.objects.create(name='Rhonda')
             authors = Author.objects.filter(name__lower__exact='john smith')
@@ -38,5 +38,3 @@ class LowerTests(TestCase):
                 authors.order_by('name'), ['John Smith'],
                 lambda a: a.name
             )
-        finally:
-            CharField._unregister_lookup(Lower)

tests/db_functions/text/test_ord.py

@@ -1,6 +1,7 @@
 from django.db.models import CharField, Value
 from django.db.models.functions import Left, Ord
 from django.test import TestCase
+from django.test.utils import register_lookup
 
 from ..models import Author
 
@@ -18,10 +19,7 @@ class OrdTests(TestCase):
         self.assertCountEqual(authors.exclude(name_part__gt=Ord(Value('John'))), [self.john])
 
     def test_transform(self):
-        try:
-            CharField.register_lookup(Ord)
+        with register_lookup(CharField, Ord):
             authors = Author.objects.annotate(first_initial=Left('name', 1))
             self.assertCountEqual(authors.filter(first_initial__ord=ord('J')), [self.john])
             self.assertCountEqual(authors.exclude(first_initial__ord=ord('J')), [self.elena, self.rhonda])
-        finally:
-            CharField._unregister_lookup(Ord)

tests/db_functions/text/test_trim.py

@@ -1,6 +1,7 @@
 from django.db.models import CharField
 from django.db.models.functions import LTrim, RTrim, Trim
 from django.test import TestCase
+from django.test.utils import register_lookup
 
 from ..models import Author
 
@@ -32,9 +33,6 @@ class TrimTests(TestCase):
         )
         for transform, trimmed_name in tests:
             with self.subTest(transform=transform):
-                try:
-                    CharField.register_lookup(transform)
+                with register_lookup(CharField, transform):
                     authors = Author.objects.filter(**{'name__%s' % transform.lookup_name: trimmed_name})
                     self.assertQuerysetEqual(authors, [' John  '], lambda a: a.name)
-                finally:
-                    CharField._unregister_lookup(transform)

tests/db_functions/text/test_upper.py

@@ -1,6 +1,7 @@
 from django.db.models import CharField
 from django.db.models.functions import Upper
 from django.test import TestCase
+from django.test.utils import register_lookup
 
 from ..models import Author
 
@@ -28,8 +29,7 @@ class UpperTests(TestCase):
         )
 
     def test_transform(self):
-        try:
-            CharField.register_lookup(Upper)
+        with register_lookup(CharField, Upper):
             Author.objects.create(name='John Smith', alias='smithj')
             Author.objects.create(name='Rhonda')
             authors = Author.objects.filter(name__upper__exact='JOHN SMITH')
@@ -39,5 +39,3 @@ class UpperTests(TestCase):
                 ],
                 lambda a: a.name
             )
-        finally:
-            CharField._unregister_lookup(Upper)