diff --git a/tests/backends/base/test_creation.py b/tests/backends/base/test_creation.py
index 340eaafc895..eb6004f8982 100644
--- a/tests/backends/base/test_creation.py
+++ b/tests/backends/base/test_creation.py
@@ -8,19 +8,21 @@ from django.db.backends.base.creation import (
 from django.test import SimpleTestCase
 
 
+def get_connection_copy():
+    # Get a copy of the default connection. (Can't use django.db.connection
+    # because it'll modify the default connection itself.)
+    test_connection = copy.copy(connections[DEFAULT_DB_ALIAS])
+    test_connection.settings_dict = copy.deepcopy(
+        connections[DEFAULT_DB_ALIAS].settings_dict
+    )
+    return test_connection
+
+
 class TestDbSignatureTests(SimpleTestCase):
-
-    def get_connection_copy(self):
-        # Get a copy of the default connection. (Can't use django.db.connection
-        # because it'll modify the default connection itself.)
-        test_connection = copy.copy(connections[DEFAULT_DB_ALIAS])
-        test_connection.settings_dict = copy.copy(connections[DEFAULT_DB_ALIAS].settings_dict)
-        return test_connection
-
     def test_default_name(self):
         # A test db name isn't set.
         prod_name = 'hodor'
-        test_connection = self.get_connection_copy()
+        test_connection = get_connection_copy()
         test_connection.settings_dict['NAME'] = prod_name
         test_connection.settings_dict['TEST'] = {'NAME': None}
         signature = BaseDatabaseCreation(test_connection).test_db_signature()
@@ -29,7 +31,7 @@ class TestDbSignatureTests(SimpleTestCase):
     def test_custom_test_name(self):
         # A regular test db name is set.
         test_name = 'hodor'
-        test_connection = self.get_connection_copy()
+        test_connection = get_connection_copy()
         test_connection.settings_dict['TEST'] = {'NAME': test_name}
         signature = BaseDatabaseCreation(test_connection).test_db_signature()
         self.assertEqual(signature[3], test_name)
@@ -37,7 +39,7 @@ class TestDbSignatureTests(SimpleTestCase):
     def test_custom_test_name_with_test_prefix(self):
         # A test db name prefixed with TEST_DATABASE_PREFIX is set.
         test_name = TEST_DATABASE_PREFIX + 'hodor'
-        test_connection = self.get_connection_copy()
+        test_connection = get_connection_copy()
         test_connection.settings_dict['TEST'] = {'NAME': test_name}
         signature = BaseDatabaseCreation(test_connection).test_db_signature()
         self.assertEqual(signature[3], test_name)