Refs #32233 -- Added tests for nonexistent cache and databases aliases.

tests/cache/tests.py

@@ -2499,3 +2499,8 @@ class CacheHandlerTest(SimpleTestCase):
             t.join()
 
         self.assertIsNot(c[0], c[1])
+
+    def test_nonexistent_alias(self):
+        msg = "Could not find config for 'nonexistent' in settings.CACHES"
+        with self.assertRaisesMessage(InvalidCacheBackendError, msg):
+            caches['nonexistent']

tests/db_utils/tests.py

@@ -3,7 +3,9 @@ import unittest
 
 from django.core.exceptions import ImproperlyConfigured
 from django.db import DEFAULT_DB_ALIAS, ProgrammingError, connection
-from django.db.utils import ConnectionHandler, load_backend
+from django.db.utils import (
+    ConnectionDoesNotExist, ConnectionHandler, load_backend,
+)
 from django.test import SimpleTestCase, TestCase
 
 
@@ -38,6 +40,30 @@ class ConnectionHandlerTests(SimpleTestCase):
         with self.assertRaisesMessage(ImproperlyConfigured, msg):
             conns['other'].ensure_connection()
 
+    def test_nonexistent_alias(self):
+        msg = "The connection nonexistent doesn't exist"
+        conns = ConnectionHandler({
+            DEFAULT_DB_ALIAS: {'ENGINE': 'django.db.backends.dummy'},
+        })
+        with self.assertRaisesMessage(ConnectionDoesNotExist, msg):
+            conns['nonexistent']
+
+    def test_ensure_defaults_nonexistent_alias(self):
+        msg = "The connection nonexistent doesn't exist"
+        conns = ConnectionHandler({
+            DEFAULT_DB_ALIAS: {'ENGINE': 'django.db.backends.dummy'},
+        })
+        with self.assertRaisesMessage(ConnectionDoesNotExist, msg):
+            conns.ensure_defaults('nonexistent')
+
+    def test_prepare_test_settings_nonexistent_alias(self):
+        msg = "The connection nonexistent doesn't exist"
+        conns = ConnectionHandler({
+            DEFAULT_DB_ALIAS: {'ENGINE': 'django.db.backends.dummy'},
+        })
+        with self.assertRaisesMessage(ConnectionDoesNotExist, msg):
+            conns.prepare_test_settings('nonexistent')
+
 
 class DatabaseErrorWrapperTests(TestCase):