Properly cleanup Tee, which reveals some resource leakage.

In particular we have a few unclose FDs. and a couple of deprecated
usage that show up, as the Tees where swallowing errors.

IPython/utils/tests/test_io.py

@@ -1,93 +1,93 b''
 # encoding: utf-8
 """Tests for io.py"""
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 
 import io as stdlib_io
 import os.path
 import stat
 import sys
 from io import StringIO
 
 from subprocess import Popen, PIPE
 import unittest
 
 import nose.tools as nt
 
 from IPython.testing.decorators import skipif, skip_win32
 from IPython.utils.io import IOStream, Tee, capture_output
 from IPython.utils.tempdir import TemporaryDirectory
 
 
 def test_tee_simple():
     "Very simple check with stdout only"
     chan = StringIO()
     text = 'Hello'
     tee = Tee(chan, channel='stdout')
     print(text, file=chan)
     nt.assert_equal(chan.getvalue(), text+"\n")
 
 
 class TeeTestCase(unittest.TestCase):
 
-    def tchan(self, channel, check='close'):
+    def tchan(self, channel):
         trap = StringIO()
         chan = StringIO()
         text = 'Hello'
         
         std_ori = getattr(sys, channel)
         setattr(sys, channel, trap)
 
         tee = Tee(chan, channel=channel)
+
         print(text, end='', file=chan)
-        setattr(sys, channel, std_ori)
         trap_val = trap.getvalue()
         nt.assert_equal(chan.getvalue(), text)
-        if check=='close':
-            tee.close()
-        else:
-            del tee
+
+        tee.close()
+
+        setattr(sys, channel, std_ori)
+        assert getattr(sys, channel) == std_ori
 
     def test(self):
         for chan in ['stdout', 'stderr']:
-            for check in ['close', 'del']:
-                self.tchan(chan, check)
+            self.tchan(chan)
 
 def test_io_init():
     """Test that io.stdin/out/err exist at startup"""
     for name in ('stdin', 'stdout', 'stderr'):
         cmd = "from IPython.utils import io;print(io.%s.__class__)"%name
-        p = Popen([sys.executable, '-c', cmd],
-                    stdout=PIPE)
-        p.wait()
-        classname = p.stdout.read().strip().decode('ascii')
+        with Popen([sys.executable, '-c', cmd], stdout=PIPE) as p:
+            p.wait()
+            classname = p.stdout.read().strip().decode('ascii')
         # __class__ is a reference to the class object in Python 3, so we can't
         # just test for string equality.
         assert 'IPython.utils.io.IOStream' in classname, classname
 
 def test_IOStream_init():
     """IOStream initializes from a file-like object missing attributes. """
     # Cause a failure from getattr and dir(). (Issue #6386)
     class BadStringIO(StringIO):
         def __dir__(self):
             attrs = super(StringIO, self).__dir__()
             attrs.append('name')
             return attrs
 
     iostream = IOStream(BadStringIO())
     iostream.write('hi, bad iostream\n')
     assert not hasattr(iostream, 'name')
+    iostream.close()
 
 def test_capture_output():
     """capture_output() context works"""
     
     with capture_output() as io:
         print('hi, stdout')
         print('hi, stderr', file=sys.stderr)
     
     nt.assert_equal(io.stdout, 'hi, stdout\n')
     nt.assert_equal(io.stderr, 'hi, stderr\n')