Fixed #29363 -- Added SimpleTestCase.assertWarnsMessage().

1 files changed, 6 insertions, 11 deletions

diff --git a/tests/from_db_value/test_deprecated.py b/tests/from_db_value/test_deprecated.py
index f0e7ed92b7..75539b3a8d 100644
--- a/tests/from_db_value/test_deprecated.py
+++ b/tests/from_db_value/test_deprecated.py
@@ -1,6 +1,5 @@
-import warnings
-
 from django.test import TestCase
+from django.utils.deprecation import RemovedInDjango30Warning
 
 from .models import Cash, CashModelDeprecated
 
@@ -8,15 +7,11 @@ from .models import Cash, CashModelDeprecated
 class FromDBValueDeprecationTests(TestCase):
 
     def test_deprecation(self):
-        CashModelDeprecated.objects.create(cash='12.50')
-        with warnings.catch_warnings(record=True) as warns:
-            warnings.simplefilter('always')
-            instance = CashModelDeprecated.objects.get()
-        self.assertIsInstance(instance.cash, Cash)
-        self.assertEqual(len(warns), 1)
-        msg = str(warns[0].message)
-        self.assertEqual(
-            msg,
+        msg = (
             'Remove the context parameter from CashFieldDeprecated.from_db_value(). '
             'Support for it will be removed in Django 3.0.'
         )
+        CashModelDeprecated.objects.create(cash='12.50')
+        with self.assertWarnsMessage(RemovedInDjango30Warning, msg):
+            instance = CashModelDeprecated.objects.get()
+        self.assertIsInstance(instance.cash, Cash)