Fix test_bytes when sys.stdin is None, for example on Windows when using

pythonw.exe instead of python.exe

diff --git a/Lib/test/test_bytes.py b/Lib/test/test_bytes.py
index f350211f713aa504fe9c71744a17fc5e7c3e5656..43b6c824a8383a33567b734c9434d8895e9d795f 100644 (file)
--- a/Lib/test/test_bytes.py
+++ b/Lib/test/test_bytes.py
@@ -700,7 +700,7 @@ class BytesTest(BaseBytesTest, unittest.TestCase):
     type2test = bytes
 
     def test_buffer_is_readonly(self):
-        fd = os.dup(sys.stdin.fileno())
+        fd = os.open(__file__, os.O_RDONLY)
         with open(fd, "rb", buffering=0) as f:
             self.assertRaises(TypeError, f.readinto, b"")