Fixed #19542: Made mirroring databases for tests work with Oracle

No tests are provided because there is no sane way to test database
settings within the Django test suite.

Thanks Aymeric Augustin for review.

django/db/backends/base/creation.py

@@ -85,6 +85,13 @@ class BaseDatabaseCreation(object):
 
         return test_database_name
 
+    def set_as_test_mirror(self, primary_settings_dict):
+        """
+        Set this database up to be used in testing as a mirror of a primary database
+        whose settings are given
+        """
+        self.connection.settings_dict['NAME'] = primary_settings_dict['NAME']
+
     def serialize_db_to_string(self):
         """
         Serializes all data in the database into a JSON string.

django/db/backends/oracle/creation.py

@@ -94,6 +94,14 @@ class DatabaseCreation(BaseDatabaseCreation):
 
         return self.connection.settings_dict['NAME']
 
+    def set_as_test_mirror(self, primary_settings_dict):
+        """
+        Set this database up to be used in testing as a mirror of a primary database
+        whose settings are given
+        """
+        self.connection.settings_dict['USER'] = primary_settings_dict['USER']
+        self.connection.settings_dict['PASSWORD'] = primary_settings_dict['PASSWORD']
+
     def _handle_objects_preventing_db_destruction(self, cursor, parameters, verbosity, autoclobber):
         # There are objects in the test tablespace which prevent dropping it
         # The easy fix is to drop the test user -- but are we allowed to do so?

django/test/runner.py

@@ -377,8 +377,8 @@ def setup_databases(verbosity, interactive, keepdb=False, debug_sql=False, **kwa
 
     for alias, mirror_alias in mirrored_aliases.items():
         mirrors.append((alias, connections[alias].settings_dict['NAME']))
-        connections[alias].settings_dict['NAME'] = (
-            connections[mirror_alias].settings_dict['NAME'])
+        connections[alias].creation.set_as_test_mirror(
+            connections[mirror_alias].settings_dict)
 
     if debug_sql:
         for alias in connections: