1 files changed, 9 insertions, 0 deletions
diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py
index df3f750..391d08c 100644
--- a/Lib/test/test_subprocess.py
+++ b/Lib/test/test_subprocess.py
@@ -2735,6 +2735,15 @@ class Win32ProcessTestCase(BaseTestCase):
                           stdout=subprocess.PIPE,
                           close_fds=True)
 
+    @support.cpython_only
+    def test_issue31471(self):
+        # There shouldn't be an assertion failure in Popen() in case the env
+        # argument has a bad keys() method.
+        class BadEnv(dict):
+            keys = None
+        with self.assertRaises(TypeError):
+            subprocess.Popen([sys.executable, "-c", "pass"], env=BadEnv())
+
     def test_close_fds(self):
         # close file descriptors
         rc = subprocess.call([sys.executable, "-c",