text: # Licensed to the .NET Foundation under one or more agreements.
  # The .NET Foundation licenses this file to you under the Apache 2.0 License.
  # See the LICENSE file in the project root for more information.
  
  import io
  import os
  import unittest
  
  from iptest import run_test
  
  class BufferedWriterTest(unittest.TestCase):
      def test_flush(self):        
          # calling flush on the BufferedWriter shouldn't flush the underlying raw
          # https://github.com/IronLanguages/ironpython3/issues/392
          b = io.BytesIO()
          f = io.BufferedWriter(io.BufferedWriter(b))
          f.write(b"a")
          f.flush()
          self.assertEqual(b.getvalue(), b"")
          f.raw.flush()
          self.assertEqual(b.getvalue(), b"a")
  
  run_test(__name__)