[1.8.x] Fixed #25745 -- Promoted RuntimeWarnings to errors in the test suite.

Conflicts:
	tests/apps/tests.py
	tests/migrations/test_graph.py
	tests/queryset_pickle/tests.py
	tests/runtests.py

Backport of 1c5f4e86bc from master

tests/apps/tests.py

@@ -2,7 +2,6 @@ from __future__ import unicode_literals
 
 import os
 import sys
-import warnings
 from unittest import skipUnless
 
 from django.apps import AppConfig, apps
@@ -229,14 +228,13 @@ class AppsTests(TestCase):
         body = {}
         body['Meta'] = type(str("Meta"), tuple(), meta_contents)
         body['__module__'] = TotallyNormal.__module__
-        with warnings.catch_warnings(record=True) as w:
+        msg = (
+            "Model 'apps.southponies' was already registered. "
+            "Reloading models is not advised as it can lead to inconsistencies, "
+            "most notably with related models."
+        )
+        with self.assertRaisesMessage(RuntimeWarning, msg):
             type(str("SouthPonies"), (models.Model,), body)
-            self.assertEqual(len(w), 1)
-            self.assertTrue(issubclass(w[-1].category, RuntimeWarning))
-            self.assertEqual(str(w[-1].message),
-                 "Model 'apps.southponies' was already registered. "
-                 "Reloading models is not advised as it can lead to inconsistencies, "
-                 "most notably with related models.")
 
         # If it doesn't appear to be a reloaded module then we expect
         # a RuntimeError.

tests/backends/tests.py

@@ -204,6 +204,7 @@ class PostgreSQLTests(TestCase):
         with warnings.catch_warnings(record=True) as w:
             with mock.patch('django.db.backends.base.base.BaseDatabaseWrapper.connect',
                             side_effect=mocked_connect, autospec=True):
+                warnings.simplefilter('always', RuntimeWarning)
                 nodb_conn = connection._nodb_connection
         del connection._nodb_connection
         self.assertIsNotNone(nodb_conn.settings_dict['NAME'])

tests/model_regress/test_pickle.py

@@ -3,13 +3,11 @@ import os
 import pickle
 import subprocess
 import sys
-import warnings
 
 from django.core.files.temp import NamedTemporaryFile
 from django.db import DJANGO_VERSION_PICKLE_KEY, models
 from django.test import TestCase, mock
 from django.utils._os import npath, upath
-from django.utils.encoding import force_text
 from django.utils.version import get_version
 
 from .models import Article
@@ -31,11 +29,9 @@ class ModelPickleTestCase(TestCase):
                 return reduce_list
 
         p = MissingDjangoVersion(title="FooBar")
-        with warnings.catch_warnings(record=True) as recorded:
+        msg = "Pickled model instance's Django version is not specified."
+        with self.assertRaisesMessage(RuntimeWarning, msg):
             pickle.loads(pickle.dumps(p))
-            msg = force_text(recorded.pop().message)
-            self.assertEqual(msg,
-                "Pickled model instance's Django version is not specified.")
 
     def test_unsupported_unpickle(self):
         """
@@ -52,14 +48,9 @@ class ModelPickleTestCase(TestCase):
                 return reduce_list
 
         p = DifferentDjangoVersion(title="FooBar")
-        with warnings.catch_warnings(record=True) as recorded:
+        msg = "Pickled model instance's Django version 1.0 does not match the current version %s." % get_version()
+        with self.assertRaisesMessage(RuntimeWarning, msg):
             pickle.loads(pickle.dumps(p))
-            msg = force_text(recorded.pop().message)
-            self.assertEqual(
-                msg,
-                "Pickled model instance's Django version 1.0 does not "
-                "match the current version %s." % get_version()
-            )
 
     def test_unpickling_when_appregistrynotready(self):
         """

tests/queryset_pickle/tests.py

@@ -2,10 +2,8 @@ from __future__ import unicode_literals
 
 import datetime
 import pickle
-import warnings
 
 from django.test import TestCase
-from django.utils.encoding import force_text
 from django.utils.version import get_version
 
 from .models import Container, Event, Group, Happening, M2MModel
@@ -140,11 +138,9 @@ class PickleabilityTestCase(TestCase):
         unpickled without a Django version
         """
         qs = Group.missing_django_version_objects.all()
-        with warnings.catch_warnings(record=True) as recorded:
+        msg = "Pickled queryset instance's Django version is not specified."
+        with self.assertRaisesMessage(RuntimeWarning, msg):
             pickle.loads(pickle.dumps(qs))
-            msg = force_text(recorded.pop().message)
-            self.assertEqual(msg,
-                "Pickled queryset instance's Django version is not specified.")
 
     def test_unsupported_unpickle(self):
         """
@@ -152,11 +148,6 @@ class PickleabilityTestCase(TestCase):
         unpickled with a different Django version than the current
         """
         qs = Group.previous_django_version_objects.all()
-        with warnings.catch_warnings(record=True) as recorded:
+        msg = "Pickled queryset instance's Django version 1.0 does not match the current version %s." % get_version()
+        with self.assertRaisesMessage(RuntimeWarning, msg):
             pickle.loads(pickle.dumps(qs))
-            msg = force_text(recorded.pop().message)
-            self.assertEqual(
-                msg,
-                "Pickled queryset instance's Django version 1.0 does not "
-                "match the current version %s." % get_version()
-            )

tests/runtests.py

@@ -23,6 +23,8 @@ from django.utils.deprecation import (
 # Make deprecation warnings errors to ensure no usage of deprecated features.
 warnings.simplefilter("error", RemovedInDjango19Warning)
 warnings.simplefilter("error", RemovedInDjango110Warning)
+# Make runtime warning errors to ensure no usage of error prone patterns.
+warnings.simplefilter("error", RuntimeWarning)
 # Ignore known warnings in test dependencies.
 warnings.filterwarnings("ignore", "'U' mode is deprecated", DeprecationWarning, module='docutils.io')