bpo-41385: Fix test_executable_without_cwd on Windows (GH-21608)

diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py
index 0162424e2fd6b690dc63efd1c9a16ebed5a24121..434ba567db0a5604d8824e1cab7b55c51fabe8cf 100644 (file)
--- a/Lib/test/test_subprocess.py
+++ b/Lib/test/test_subprocess.py
@@ -376,7 +376,9 @@ class ProcessTestCase(BaseTestCase):
         # matches *expected_cwd*.
         p = subprocess.Popen([python_arg, "-c",
                               "import os, sys; "
-                              "sys.stdout.write(os.getcwd()); "
+                              "buf = sys.stdout.buffer; "
+                              "buf.write(os.getcwd().encode()); "
+                              "buf.flush(); "
                               "sys.exit(47)"],
                               stdout=subprocess.PIPE,
                               **kwargs)
@@ -385,7 +387,7 @@ class ProcessTestCase(BaseTestCase):
         self.assertEqual(47, p.returncode)
         normcase = os.path.normcase
         self.assertEqual(normcase(expected_cwd),
-                         normcase(p.stdout.read().decode("utf-8")))
+                         normcase(p.stdout.read().decode()))
 
     def test_cwd(self):
         # Check that cwd changes the cwd for the child process.