Avoided modifying current environment in admin_scripts tests

tests/admin_scripts/tests.py

@@ -122,35 +122,29 @@ class AdminScriptTestCase(unittest.TestCase):
         django_dir = os.path.dirname(tests_dir)
         ext_backend_base_dirs = self._ext_backend_paths()
 
-        # Remember the old environment
-        old_django_settings_module = os.environ.get('DJANGO_SETTINGS_MODULE', None)
+        # Define a temporary environment for the subprocess
+        test_environ = os.environ.copy()
         if sys.platform.startswith('java'):
             python_path_var_name = 'JYTHONPATH'
         else:
             python_path_var_name = 'PYTHONPATH'
 
-        old_python_path = os.environ.get(python_path_var_name, None)
         old_cwd = os.getcwd()
 
         # Set the test environment
         if settings_file:
-            os.environ['DJANGO_SETTINGS_MODULE'] = settings_file
-        elif 'DJANGO_SETTINGS_MODULE' in os.environ:
-            del os.environ['DJANGO_SETTINGS_MODULE']
+            test_environ['DJANGO_SETTINGS_MODULE'] = settings_file
+        elif 'DJANGO_SETTINGS_MODULE' in test_environ:
+            del test_environ['DJANGO_SETTINGS_MODULE']
         python_path = [base_dir, django_dir, tests_dir]
         python_path.extend(ext_backend_base_dirs)
-        os.environ[python_path_var_name] = os.pathsep.join(python_path)
+        test_environ[python_path_var_name] = os.pathsep.join(python_path)
 
         # Move to the test directory and run
         os.chdir(test_dir)
         out, err = subprocess.Popen([sys.executable, script] + args,
                 stdout=subprocess.PIPE, stderr=subprocess.PIPE,
-                universal_newlines=True).communicate()
-        # Restore the old environment
-        if old_django_settings_module:
-            os.environ['DJANGO_SETTINGS_MODULE'] = old_django_settings_module
-        if old_python_path:
-            os.environ[python_path_var_name] = old_python_path
+                env=test_environ, universal_newlines=True).communicate()
         # Move back to the old working directory
         os.chdir(old_cwd)