Index: Lib/test/test_subprocess.py
===================================================================
--- Lib/test/test_subprocess.py	(revision 73407)
+++ Lib/test/test_subprocess.py	(working copy)
@@ -537,6 +537,55 @@
             except (IOError, OSError) as err:
                 if err.errno != 2:  # ignore "no such file"
                     raise
+    
+    def test_encoded_stdout(self):
+        send = '\xef'
+        encoding = 'utf-8'
+        script = """
+import os
+import sys
+send = %(send)r.encode(%(encoding)r)
+while send:
+    sent = os.write(sys.stdout.fileno(), send)
+    send = send[sent:]
+""" % {'send': send, 'encoding': encoding}
+        p = subprocess.Popen([sys.executable, "-c", script],
+                             encoding=encoding, stdout=subprocess.PIPE)
+        self.assertEqual(p.stdout.read(), send)
+    
+    def test_encoded_stderr(self):
+        send = '\xef'
+        encoding = 'utf-8'
+        script = """
+import os
+import sys
+send = %(send)r.encode(%(encoding)r)
+while send:
+    sent = os.write(sys.stderr.fileno(), send)
+    send = send[sent:]
+""" % {'send': send, 'encoding': encoding}
+        p = subprocess.Popen([sys.executable, "-c", script],
+                             encoding=encoding, stderr=subprocess.PIPE)
+        self.assertEqual(p.stderr.read(), send)
+    
+    def test_encoded_stdin(self):
+        send = '\xef'
+        encoding = 'utf-8'
+        script = """
+import os
+import sys
+send = %(send)r.encode(%(encoding)r)
+recv = bytes()
+while len(recv) != len(send):
+    recv += os.read(sys.stdin.fileno(), len(send) - len(recv))
+if send != recv:
+    sys.exit(1)
+""" % {'send': send, 'encoding': encoding}
+        p = subprocess.Popen([sys.executable, "-c", script],
+                             encoding=encoding, stdin=subprocess.PIPE)
+        p.stdin.write(send)
+        p.stdin.flush()
+        self.assertEqual(p.wait(), 0)
 
     #
     # POSIX tests