From 178148025494c4058571831fb11fc8eeff8b7365 Mon Sep 17 00:00:00 2001
From: "Miss Islington (bot)"
 <31488909+miss-islington@users.noreply.github.com>
Date: Tue, 17 Oct 2017 18:47:10 -0700
Subject: bpo-31676: Fix test_imp.test_load_source() side effect (GH-3871)
 (GH-3988)

test_load_source() now replaces the current __name__ module with a
temporary module to prevent side effects.
(cherry picked from commit a505ecdc5013cd8f930aacc1ec4fb2afa62d3853)
---
 Lib/test/test_imp.py | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/Lib/test/test_imp.py b/Lib/test/test_imp.py
index d513eed..1c7605c 100644
--- a/Lib/test/test_imp.py
+++ b/Lib/test/test_imp.py
@@ -315,8 +315,13 @@ class ImportTests(unittest.TestCase):
         loader.get_data(imp.__file__)  # Will need to create a newly opened file
 
     def test_load_source(self):
-        with self.assertRaisesRegex(ValueError, 'embedded null'):
-            imp.load_source(__name__, __file__ + "\0")
+        # Create a temporary module since load_source(name) modifies
+        # sys.modules[name] attributes like __loader___
+        modname = f"tmp{__name__}"
+        mod = type(sys.modules[__name__])(modname)
+        with support.swap_item(sys.modules, modname, mod):
+            with self.assertRaisesRegex(ValueError, 'embedded null'):
+                imp.load_source(modname, __file__ + "\0")
 
     @support.cpython_only
     def test_issue31315(self):
-- 
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