1 files changed, 10 insertions, 0 deletions
diff --git a/Lib/test/libregrtest/setup.py b/Lib/test/libregrtest/setup.py
index 83ce2f73f4..472c6ebec0 100644
--- a/Lib/test/libregrtest/setup.py
+++ b/Lib/test/libregrtest/setup.py
@@ -14,6 +14,9 @@ from test.libregrtest.utils import (setup_unraisable_hook,
                                     setup_threading_excepthook)
 
 
+UNICODE_GUARD_ENV = "PYTHONREGRTEST_UNICODE_GUARD"
+
+
 def setup_tests(ns):
     try:
         stderr_fd = sys.__stderr__.fileno()
@@ -99,6 +102,13 @@ def setup_tests(ns):
         from test.support.testresult import RegressionTestResult
         RegressionTestResult.USE_XML = True
 
+    # Ensure there's a non-ASCII character in env vars at all times to force
+    # tests consider this case. See BPO-44647 for details.
+    os.environ.setdefault(
+        UNICODE_GUARD_ENV,
+        "\N{SMILING FACE WITH SUNGLASSES}",
+    )
+
 
 def replace_stdout():
     """Set stdout encoder error handler to backslashreplace (as stderr error