Add AssertPrints context manager to check output from tests.

IPython/testing/tests/test_tools.py

@@ -1,73 +1,90 b''
 # encoding: utf-8
 """
 Tests for testing.tools
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2009  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 from __future__ import with_statement
 
 import os
 import sys
+import unittest
 
 import nose.tools as nt
 
 from IPython.testing import decorators as dec
 from IPython.testing import tools as tt
 
 #-----------------------------------------------------------------------------
 # Tests
 #-----------------------------------------------------------------------------
 
 @dec.skip_win32
 def test_full_path_posix():
     spath = '/foo/bar.py'
     result = tt.full_path(spath,['a.txt','b.txt'])
     nt.assert_equal(result, ['/foo/a.txt', '/foo/b.txt'])
     spath = '/foo'
     result = tt.full_path(spath,['a.txt','b.txt'])
     nt.assert_equal(result, ['/a.txt', '/b.txt'])
     result = tt.full_path(spath,'a.txt')
     nt.assert_equal(result, ['/a.txt'])
 
 
 @dec.skip_if_not_win32
 def test_full_path_win32():
     spath = 'c:\\foo\\bar.py'
     result = tt.full_path(spath,['a.txt','b.txt'])
     nt.assert_equal(result, ['c:\\foo\\a.txt', 'c:\\foo\\b.txt'])
     spath = 'c:\\foo'
     result = tt.full_path(spath,['a.txt','b.txt'])
     nt.assert_equal(result, ['c:\\a.txt', 'c:\\b.txt'])
     result = tt.full_path(spath,'a.txt')
     nt.assert_equal(result, ['c:\\a.txt'])
 
     
 @dec.parametric
 def test_parser():
     err = ("FAILED (errors=1)", 1, 0)
     fail = ("FAILED (failures=1)", 0, 1)
     both = ("FAILED (errors=1, failures=1)", 1, 1)
     for txt, nerr, nfail in [err, fail, both]:
         nerr1, nfail1 = tt.parse_test_output(txt)
         yield nt.assert_equal(nerr, nerr1)
         yield nt.assert_equal(nfail, nfail1)
 
         
 @dec.parametric
 def test_temp_pyfile():
     src = 'pass\n'
     fname, fh = tt.temp_pyfile(src)
     yield nt.assert_true(os.path.isfile(fname))
     fh.close()
     with open(fname) as fh2:
         src2 = fh2.read()
     yield nt.assert_equal(src2, src)
+
+class TestAssertPrints(unittest.TestCase):
+    def test_passing(self):
+        with tt.AssertPrints("abc"):
+            print "abcd"
+            print "def"
+            print b"ghi"
+    
+    def test_failing(self):
+        def func():
+            with tt.AssertPrints("abc"):
+                print "acd"
+                print "def"
+                print b"ghi"
+        
+        self.assertRaises(AssertionError, func)

IPython/testing/tools.py

@@ -1,346 +1,388 b''
 """Generic testing tools that do NOT depend on Twisted.
 
 In particular, this module exposes a set of top-level assert* functions that
 can be used in place of nose.tools.assert* in method generators (the ones in
 nose can not, at least as of nose 0.10.4).
 
 Note: our testing package contains testing.util, which does depend on Twisted
 and provides utilities for tests that manage Deferreds.  All testing support
 tools that only depend on nose, IPython or the standard library should go here
 instead.
 
 
 Authors
 -------
 - Fernando Perez <[e-mail]>
 """
 
 from __future__ import absolute_import
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2009  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import os
 import re
 import sys
 import tempfile
 
 from contextlib import contextmanager
+from io import StringIO
 
 try:
     # These tools are used by parts of the runtime, so we make the nose
     # dependency optional at this point.  Nose is a hard dependency to run the
     # test suite, but NOT to use ipython itself.
     import nose.tools as nt
     has_nose = True
 except ImportError:
     has_nose = False
 
 from IPython.config.loader import Config
 from IPython.utils.process import find_cmd, getoutputerror
-from IPython.utils.text import list_strings
-from IPython.utils.io import temp_pyfile
-from IPython.utils.py3compat import PY3
+from IPython.utils.text import list_strings, getdefaultencoding
+from IPython.utils.io import temp_pyfile, Tee
+from IPython.utils import py3compat
 
 from . import decorators as dec
 from . import skipdoctest
 
 #-----------------------------------------------------------------------------
 # Globals
 #-----------------------------------------------------------------------------
 
 # Make a bunch of nose.tools assert wrappers that can be used in test
 # generators.  This will expose an assert* function for each one in nose.tools.
 
 _tpl = """
 def %(name)s(*a,**kw):
     return nt.%(name)s(*a,**kw)
 """
 
 if has_nose:
     for _x in [a for a in dir(nt) if a.startswith('assert')]:
         exec _tpl % dict(name=_x)
 
 #-----------------------------------------------------------------------------
 # Functions and classes
 #-----------------------------------------------------------------------------
 
 # The docstring for full_path doctests differently on win32 (different path
 # separator) so just skip the doctest there.  The example remains informative.
 doctest_deco = skipdoctest.skip_doctest if sys.platform == 'win32' else dec.null_deco
 
 @doctest_deco
 def full_path(startPath,files):
     """Make full paths for all the listed files, based on startPath.
 
     Only the base part of startPath is kept, since this routine is typically
     used with a script's __file__ variable as startPath.  The base of startPath
     is then prepended to all the listed files, forming the output list.
 
     Parameters
     ----------
       startPath : string
         Initial path to use as the base for the results.  This path is split
       using os.path.split() and only its first component is kept.
 
       files : string or list
         One or more files.
 
     Examples
     --------
 
     >>> full_path('/foo/bar.py',['a.txt','b.txt'])
     ['/foo/a.txt', '/foo/b.txt']
 
     >>> full_path('/foo',['a.txt','b.txt'])
     ['/a.txt', '/b.txt']
 
     If a single file is given, the output is still a list:
     >>> full_path('/foo','a.txt')
     ['/a.txt']
     """
 
     files = list_strings(files)
     base = os.path.split(startPath)[0]
     return [ os.path.join(base,f) for f in files ]
 
 
 def parse_test_output(txt):
     """Parse the output of a test run and return errors, failures.
 
     Parameters
     ----------
     txt : str
       Text output of a test run, assumed to contain a line of one of the
       following forms::
         'FAILED (errors=1)'
         'FAILED (failures=1)'
         'FAILED (errors=1, failures=1)'
 
     Returns
     -------
     nerr, nfail: number of errors and failures.
     """
 
     err_m = re.search(r'^FAILED \(errors=(\d+)\)', txt, re.MULTILINE)
     if err_m:
         nerr = int(err_m.group(1))
         nfail = 0
         return  nerr, nfail
 
     fail_m = re.search(r'^FAILED \(failures=(\d+)\)', txt, re.MULTILINE)
     if fail_m:
         nerr = 0
         nfail = int(fail_m.group(1))
         return  nerr, nfail
 
     both_m = re.search(r'^FAILED \(errors=(\d+), failures=(\d+)\)', txt,
                        re.MULTILINE)
     if both_m:
         nerr = int(both_m.group(1))
         nfail = int(both_m.group(2))
         return  nerr, nfail
 
     # If the input didn't match any of these forms, assume no error/failures
     return 0, 0
 
 
 # So nose doesn't think this is a test
 parse_test_output.__test__ = False
 
 
 def default_argv():
     """Return a valid default argv for creating testing instances of ipython"""
 
     return ['--quick', # so no config file is loaded
             # Other defaults to minimize side effects on stdout
             '--colors=NoColor', '--no-term-title','--no-banner',
             '--autocall=0']
 
 
 def default_config():
     """Return a config object with good defaults for testing."""
     config = Config()
     config.TerminalInteractiveShell.colors = 'NoColor'
     config.TerminalTerminalInteractiveShell.term_title = False,
     config.TerminalInteractiveShell.autocall = 0
     config.HistoryManager.hist_file = tempfile.mktemp(u'test_hist.sqlite')
     config.HistoryManager.db_cache_size = 10000
     return config
 
 
 def ipexec(fname, options=None):
     """Utility to call 'ipython filename'.
 
     Starts IPython witha minimal and safe configuration to make startup as fast
     as possible.
 
     Note that this starts IPython in a subprocess!
 
     Parameters
     ----------
     fname : str
       Name of file to be executed (should have .py or .ipy extension).
 
     options : optional, list
       Extra command-line flags to be passed to IPython.
 
     Returns
     -------
     (stdout, stderr) of ipython subprocess.
     """
     if options is None: options = []
 
     # For these subprocess calls, eliminate all prompt printing so we only see
     # output from script execution
     prompt_opts = [ '--InteractiveShell.prompt_in1=""',
                     '--InteractiveShell.prompt_in2=""',
                     '--InteractiveShell.prompt_out=""'
     ]
     cmdargs = ' '.join(default_argv() + prompt_opts + options)
 
     _ip = get_ipython()
     test_dir = os.path.dirname(__file__)
 
-    ipython_cmd = find_cmd('ipython3' if PY3 else 'ipython')
+    ipython_cmd = find_cmd('ipython3' if py3compat.PY3 else 'ipython')
     # Absolute path for filename
     full_fname = os.path.join(test_dir, fname)
     full_cmd = '%s %s %s' % (ipython_cmd, cmdargs, full_fname)
     #print >> sys.stderr, 'FULL CMD:', full_cmd # dbg
     out = getoutputerror(full_cmd)
     # `import readline` causes 'ESC[?1034h' to be the first output sometimes,
     # so strip that off the front of the first line if it is found
     if out:
         first = out[0]
         m = re.match(r'\x1b\[[^h]+h', first)
         if m:
             # strip initial readline escape
             out = list(out)
             out[0] = first[len(m.group()):]
             out = tuple(out)
     return out
 
 
 def ipexec_validate(fname, expected_out, expected_err='',
                     options=None):
     """Utility to call 'ipython filename' and validate output/error.
 
     This function raises an AssertionError if the validation fails.
 
     Note that this starts IPython in a subprocess!
 
     Parameters
     ----------
     fname : str
       Name of the file to be executed (should have .py or .ipy extension).
 
     expected_out : str
       Expected stdout of the process.
 
     expected_err : optional, str
       Expected stderr of the process.
 
     options : optional, list
       Extra command-line flags to be passed to IPython.
 
     Returns
     -------
     None
     """
 
     import nose.tools as nt
 
     out, err = ipexec(fname)
     #print 'OUT', out  # dbg
     #print 'ERR', err  # dbg
     # If there are any errors, we must check those befor stdout, as they may be
     # more informative than simply having an empty stdout.
     if err:
         if expected_err:
             nt.assert_equals(err.strip(), expected_err.strip())
         else:
             raise ValueError('Running file %r produced error: %r' %
                              (fname, err))
     # If no errors or output on stderr was expected, match stdout
     nt.assert_equals(out.strip(), expected_out.strip())
 
 
 class TempFileMixin(object):
     """Utility class to create temporary Python/IPython files.
 
     Meant as a mixin class for test cases."""
 
     def mktmp(self, src, ext='.py'):
         """Make a valid python temp file."""
         fname, f = temp_pyfile(src, ext)
         self.tmpfile = f
         self.fname = fname
 
     def tearDown(self):
         if hasattr(self, 'tmpfile'):
             # If the tmpfile wasn't made because of skipped tests, like in
             # win32, there's nothing to cleanup.
             self.tmpfile.close()
             try:
                 os.unlink(self.fname)
             except:
                 # On Windows, even though we close the file, we still can't
                 # delete it.  I have no clue why
                 pass
 
 pair_fail_msg = ("Testing {0}\n\n"
                 "In:\n"
                 "  {1!r}\n"
                 "Expected:\n"
                 "  {2!r}\n"
                 "Got:\n"
                 "  {3!r}\n")
 def check_pairs(func, pairs):
     """Utility function for the common case of checking a function with a
     sequence of input/output pairs.
 
     Parameters
     ----------
     func : callable
       The function to be tested. Should accept a single argument.
     pairs : iterable
       A list of (input, expected_output) tuples.
 
     Returns
     -------
     None. Raises an AssertionError if any output does not match the expected
     value.
     """
     name = getattr(func, "func_name", getattr(func, "__name__", "<unknown>"))
     for inp, expected in pairs:
         out = func(inp)
         assert out == expected, pair_fail_msg.format(name, inp, expected, out)
 
+if py3compat.PY3:
+    MyStringIO = StringIO
+else:
+    # In Python 2, stdout/stderr can have either bytes or unicode written to them,
+    # so we need a class that can handle both.
+    class MyStringIO(StringIO):
+        def write(self, s):
+            s = py3compat.cast_unicode(s, encoding=getdefaultencoding())
+            super(MyStringIO, self).write(s)
+
+notprinted_msg = """Did not find {0!r} in printed output (on {1}):
+{2!r}"""
+class AssertPrints(object):
+    """Context manager for testing that code prints certain text.
+    
+    Examples
+    --------
+    >>> with AssertPrints("abc"):
+    ...     print "abcd"
+    ...     print "def"
+    ... 
+    abcd
+    def
+    """
+    def __init__(self, s, channel='stdout'):
+        self.s = s
+        self.channel = channel
+    
+    def __enter__(self):
+        self.orig_stream = getattr(sys, self.channel)
+        self.buffer = MyStringIO()
+        self.tee = Tee(self.buffer, channel=self.channel)
+        setattr(sys, self.channel, self.tee)
+    
+    def __exit__(self, etype, value, traceback):
+        self.tee.flush()
+        setattr(sys, self.channel, self.orig_stream)
+        printed = self.buffer.getvalue()
+        assert self.s in printed, notprinted_msg.format(self.s, self.channel, printed)
+        return False
+
 @contextmanager
 def mute_warn():
     from IPython.utils import warn
     save_warn = warn.warn
     warn.warn = lambda *a, **kw: None
     try:
         yield
     finally:
         warn.warn = save_warn
 
 @contextmanager
 def make_tempfile(name):
     """ Create an empty, named, temporary file for the duration of the context.
     """
     f = open(name, 'w')
     f.close()
     try:
         yield
     finally:
         os.unlink(name)

IPython/utils/tests/test_path.py

@@ -1,450 +1,445 b''
 # encoding: utf-8
 """Tests for IPython.utils.path.py"""
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 from __future__ import with_statement
 
 import os
 import shutil
 import sys
 import tempfile
 from io import StringIO
 
 from os.path import join, abspath, split
 
 import nose.tools as nt
 
 from nose import with_setup
 
 import IPython
 from IPython.testing import decorators as dec
 from IPython.testing.decorators import skip_if_not_win32, skip_win32
-from IPython.testing.tools import make_tempfile
+from IPython.testing.tools import make_tempfile, AssertPrints
 from IPython.utils import path, io
 from IPython.utils import py3compat
 
 # Platform-dependent imports
 try:
     import _winreg as wreg
 except ImportError:
     #Fake _winreg module on none windows platforms
     import types
     wr_name = "winreg" if py3compat.PY3 else "_winreg"
     sys.modules[wr_name] = types.ModuleType(wr_name)
     import _winreg as wreg
     #Add entries that needs to be stubbed by the testing code
     (wreg.OpenKey, wreg.QueryValueEx,) = (None, None)
 
 try:
     reload
 except NameError:   # Python 3
     from imp import reload
 
 #-----------------------------------------------------------------------------
 # Globals
 #-----------------------------------------------------------------------------
 env = os.environ
 TEST_FILE_PATH = split(abspath(__file__))[0]
 TMP_TEST_DIR = tempfile.mkdtemp()
 HOME_TEST_DIR = join(TMP_TEST_DIR, "home_test_dir")
 XDG_TEST_DIR = join(HOME_TEST_DIR, "xdg_test_dir")
 IP_TEST_DIR = join(HOME_TEST_DIR,'.ipython')
 #
 # Setup/teardown functions/decorators
 #
 
 def setup():
     """Setup testenvironment for the module:
 
             - Adds dummy home dir tree
     """
     # Do not mask exceptions here.  In particular, catching WindowsError is a
     # problem because that exception is only defined on Windows...
     os.makedirs(IP_TEST_DIR)
     os.makedirs(os.path.join(XDG_TEST_DIR, 'ipython'))
 
 
 def teardown():
     """Teardown testenvironment for the module:
 
             - Remove dummy home dir tree
     """
     # Note: we remove the parent test dir, which is the root of all test
     # subdirs we may have created.  Use shutil instead of os.removedirs, so
     # that non-empty directories are all recursively removed.
     shutil.rmtree(TMP_TEST_DIR)
 
 
 def setup_environment():
     """Setup testenvironment for some functions that are tested
     in this module. In particular this functions stores attributes
     and other things that we need to stub in some test functions.
     This needs to be done on a function level and not module level because
     each testfunction needs a pristine environment.
     """
     global oldstuff, platformstuff
     oldstuff = (env.copy(), os.name, path.get_home_dir, IPython.__file__, os.getcwd())
 
     if os.name == 'nt':
         platformstuff = (wreg.OpenKey, wreg.QueryValueEx,)
 
 
 def teardown_environment():
     """Restore things that were remebered by the setup_environment function
     """
     (oldenv, os.name, path.get_home_dir, IPython.__file__, old_wd) = oldstuff
     os.chdir(old_wd)
     reload(path)
 
     for key in env.keys():
         if key not in oldenv:
             del env[key]
     env.update(oldenv)
     if hasattr(sys, 'frozen'):
         del sys.frozen
     if os.name == 'nt':
         (wreg.OpenKey, wreg.QueryValueEx,) = platformstuff
 
 # Build decorator that uses the setup_environment/setup_environment
 with_environment = with_setup(setup_environment, teardown_environment)
 
 
 @skip_if_not_win32
 @with_environment
 def test_get_home_dir_1():
     """Testcase for py2exe logic, un-compressed lib
     """
     sys.frozen = True
 
     #fake filename for IPython.__init__
     IPython.__file__ = abspath(join(HOME_TEST_DIR, "Lib/IPython/__init__.py"))
 
     home_dir = path.get_home_dir()
     nt.assert_equal(home_dir, abspath(HOME_TEST_DIR))
 
 
 @skip_if_not_win32
 @with_environment
 def test_get_home_dir_2():
     """Testcase for py2exe logic, compressed lib
     """
     sys.frozen = True
     #fake filename for IPython.__init__
     IPython.__file__ = abspath(join(HOME_TEST_DIR, "Library.zip/IPython/__init__.py")).lower()
 
     home_dir = path.get_home_dir()
     nt.assert_equal(home_dir, abspath(HOME_TEST_DIR).lower())
 
 
 @with_environment
 @skip_win32
 def test_get_home_dir_3():
     """Testcase $HOME is set, then use its value as home directory."""
     env["HOME"] = HOME_TEST_DIR
     home_dir = path.get_home_dir()
     nt.assert_equal(home_dir, env["HOME"])
 
 
 @with_environment
 @skip_win32
 def test_get_home_dir_4():
     """Testcase $HOME is not set, os=='posix'.
     This should fail with HomeDirError"""
 
     os.name = 'posix'
     if 'HOME' in env: del env['HOME']
     nt.assert_raises(path.HomeDirError, path.get_home_dir)
 
 
 @skip_if_not_win32
 @with_environment
 def test_get_home_dir_5():
     """Using HOMEDRIVE + HOMEPATH, os=='nt'.
 
     HOMESHARE is missing.
     """
 
     os.name = 'nt'
     env.pop('HOMESHARE', None)
     env['HOMEDRIVE'], env['HOMEPATH'] = os.path.splitdrive(HOME_TEST_DIR)
     home_dir = path.get_home_dir()
     nt.assert_equal(home_dir, abspath(HOME_TEST_DIR))
 
 
 @skip_if_not_win32
 @with_environment
 def test_get_home_dir_6():
     """Using USERPROFILE, os=='nt'.
 
     HOMESHARE, HOMEDRIVE, HOMEPATH are missing.
     """
 
     os.name = 'nt'
     env.pop('HOMESHARE', None)
     env.pop('HOMEDRIVE', None)
     env.pop('HOMEPATH', None)
     env["USERPROFILE"] = abspath(HOME_TEST_DIR)
     home_dir = path.get_home_dir()
     nt.assert_equal(home_dir, abspath(HOME_TEST_DIR))
 
 
 @skip_if_not_win32
 @with_environment
 def test_get_home_dir_7():
     """Using HOMESHARE, os=='nt'."""
 
     os.name = 'nt'
     env["HOMESHARE"] = abspath(HOME_TEST_DIR)
     home_dir = path.get_home_dir()
     nt.assert_equal(home_dir, abspath(HOME_TEST_DIR))
 
 
 # Should we stub wreg fully so we can run the test on all platforms?
 @skip_if_not_win32
 @with_environment
 def test_get_home_dir_8():
     """Using registry hack for 'My Documents', os=='nt'
 
     HOMESHARE, HOMEDRIVE, HOMEPATH, USERPROFILE and others are missing.
     """
     os.name = 'nt'
     # Remove from stub environment all keys that may be set
     for key in ['HOME', 'HOMESHARE', 'HOMEDRIVE', 'HOMEPATH', 'USERPROFILE']:
         env.pop(key, None)
 
     #Stub windows registry functions
     def OpenKey(x, y):
         class key:
             def Close(self):
                 pass
         return key()
     def QueryValueEx(x, y):
         return [abspath(HOME_TEST_DIR)]
 
     wreg.OpenKey = OpenKey
     wreg.QueryValueEx = QueryValueEx
 
     home_dir = path.get_home_dir()
     nt.assert_equal(home_dir, abspath(HOME_TEST_DIR))
 
 
 @with_environment
 def test_get_ipython_dir_1():
     """test_get_ipython_dir_1, Testcase to see if we can call get_ipython_dir without Exceptions."""
     env_ipdir = os.path.join("someplace", ".ipython")
     path._writable_dir = lambda path: True
     env['IPYTHON_DIR'] = env_ipdir
     ipdir = path.get_ipython_dir()
     nt.assert_equal(ipdir, env_ipdir)
 
 
 @with_environment
 def test_get_ipython_dir_2():
     """test_get_ipython_dir_2, Testcase to see if we can call get_ipython_dir without Exceptions."""
     path.get_home_dir = lambda : "someplace"
     path.get_xdg_dir = lambda : None
     path._writable_dir = lambda path: True
     os.name = "posix"
     env.pop('IPYTHON_DIR', None)
     env.pop('IPYTHONDIR', None)
     env.pop('XDG_CONFIG_HOME', None)
     ipdir = path.get_ipython_dir()
     nt.assert_equal(ipdir, os.path.join("someplace", ".ipython"))
 
 @with_environment
 def test_get_ipython_dir_3():
     """test_get_ipython_dir_3, use XDG if defined, and .ipython doesn't exist."""
     path.get_home_dir = lambda : "someplace"
     path._writable_dir = lambda path: True
     os.name = "posix"
     env.pop('IPYTHON_DIR', None)
     env.pop('IPYTHONDIR', None)
     env['XDG_CONFIG_HOME'] = XDG_TEST_DIR
     ipdir = path.get_ipython_dir()
     nt.assert_equal(ipdir, os.path.join(XDG_TEST_DIR, "ipython"))
 
 @with_environment
 def test_get_ipython_dir_4():
     """test_get_ipython_dir_4, use XDG if both exist."""
     path.get_home_dir = lambda : HOME_TEST_DIR
     os.name = "posix"
     env.pop('IPYTHON_DIR', None)
     env.pop('IPYTHONDIR', None)
     env['XDG_CONFIG_HOME'] = XDG_TEST_DIR
     xdg_ipdir = os.path.join(XDG_TEST_DIR, "ipython")
     ipdir = path.get_ipython_dir()
     nt.assert_equal(ipdir, xdg_ipdir)
 
 @with_environment
 def test_get_ipython_dir_5():
     """test_get_ipython_dir_5, use .ipython if exists and XDG defined, but doesn't exist."""
     path.get_home_dir = lambda : HOME_TEST_DIR
     os.name = "posix"
     env.pop('IPYTHON_DIR', None)
     env.pop('IPYTHONDIR', None)
     env['XDG_CONFIG_HOME'] = XDG_TEST_DIR
     os.rmdir(os.path.join(XDG_TEST_DIR, 'ipython'))
     ipdir = path.get_ipython_dir()
     nt.assert_equal(ipdir, IP_TEST_DIR)
 
 @with_environment
 def test_get_ipython_dir_6():
     """test_get_ipython_dir_6, use XDG if defined and neither exist."""
     xdg = os.path.join(HOME_TEST_DIR, 'somexdg')
     os.mkdir(xdg)
     shutil.rmtree(os.path.join(HOME_TEST_DIR, '.ipython'))
     path.get_home_dir = lambda : HOME_TEST_DIR
     path.get_xdg_dir = lambda : xdg
     os.name = "posix"
     env.pop('IPYTHON_DIR', None)
     env.pop('IPYTHONDIR', None)
     env.pop('XDG_CONFIG_HOME', None)
     xdg_ipdir = os.path.join(xdg, "ipython")
     ipdir = path.get_ipython_dir()
     nt.assert_equal(ipdir, xdg_ipdir)
 
 @with_environment
 def test_get_ipython_dir_7():
     """test_get_ipython_dir_7, test home directory expansion on IPYTHON_DIR"""
     path._writable_dir = lambda path: True
     home_dir = os.path.expanduser('~')
     env['IPYTHON_DIR'] = os.path.join('~', 'somewhere')
     ipdir = path.get_ipython_dir()
     nt.assert_equal(ipdir, os.path.join(home_dir, 'somewhere'))
 
 
 @with_environment
 def test_get_xdg_dir_1():
     """test_get_xdg_dir_1, check xdg_dir"""
     reload(path)
     path._writable_dir = lambda path: True
     path.get_home_dir = lambda : 'somewhere'
     os.name = "posix"
     env.pop('IPYTHON_DIR', None)
     env.pop('IPYTHONDIR', None)
     env.pop('XDG_CONFIG_HOME', None)
 
     nt.assert_equal(path.get_xdg_dir(), os.path.join('somewhere', '.config'))
 
 
 @with_environment
 def test_get_xdg_dir_1():
     """test_get_xdg_dir_1, check nonexistant xdg_dir"""
     reload(path)
     path.get_home_dir = lambda : HOME_TEST_DIR
     os.name = "posix"
     env.pop('IPYTHON_DIR', None)
     env.pop('IPYTHONDIR', None)
     env.pop('XDG_CONFIG_HOME', None)
     nt.assert_equal(path.get_xdg_dir(), None)
 
 @with_environment
 def test_get_xdg_dir_2():
     """test_get_xdg_dir_2, check xdg_dir default to ~/.config"""
     reload(path)
     path.get_home_dir = lambda : HOME_TEST_DIR
     os.name = "posix"
     env.pop('IPYTHON_DIR', None)
     env.pop('IPYTHONDIR', None)
     env.pop('XDG_CONFIG_HOME', None)
     cfgdir=os.path.join(path.get_home_dir(), '.config')
     os.makedirs(cfgdir)
 
     nt.assert_equal(path.get_xdg_dir(), cfgdir)
 
 def test_filefind():
     """Various tests for filefind"""
     f = tempfile.NamedTemporaryFile()
     # print 'fname:',f.name
     alt_dirs = path.get_ipython_dir()
     t = path.filefind(f.name, alt_dirs)
     # print 'found:',t
 
 
 def test_get_ipython_package_dir():
     ipdir = path.get_ipython_package_dir()
     nt.assert_true(os.path.isdir(ipdir))
 
 
 def test_get_ipython_module_path():
     ipapp_path = path.get_ipython_module_path('IPython.frontend.terminal.ipapp')
     nt.assert_true(os.path.isfile(ipapp_path))
 
 
 @dec.skip_if_not_win32
 def test_get_long_path_name_win32():
     p = path.get_long_path_name('c:\\docume~1')
     nt.assert_equals(p,u'c:\\Documents and Settings')
 
 
 @dec.skip_win32
 def test_get_long_path_name():
     p = path.get_long_path_name('/usr/local')
     nt.assert_equals(p,'/usr/local')
 
 @dec.skip_win32 # can't create not-user-writable dir on win
 @with_environment
 def test_not_writable_ipdir():
     tmpdir = tempfile.mkdtemp()
     os.name = "posix"
     env.pop('IPYTHON_DIR', None)
     env.pop('IPYTHONDIR', None)
     env.pop('XDG_CONFIG_HOME', None)
     env['HOME'] = tmpdir
     ipdir = os.path.join(tmpdir, '.ipython')
     os.mkdir(ipdir)
     os.chmod(ipdir, 600)
-    stderr = io.stderr
-    pipe = StringIO()
-    io.stderr = pipe
-    ipdir = path.get_ipython_dir()
-    io.stderr.flush()
-    io.stderr = stderr
-    nt.assert_true('WARNING' in pipe.getvalue())
+    with AssertPrints('WARNING', channel='stderr'):
+        ipdir = path.get_ipython_dir()
     env.pop('IPYTHON_DIR', None)
 
 def test_unquote_filename():
     for win32 in (True, False):
         nt.assert_equals(path.unquote_filename('foo.py', win32=win32), 'foo.py')
         nt.assert_equals(path.unquote_filename('foo bar.py', win32=win32), 'foo bar.py')
     nt.assert_equals(path.unquote_filename('"foo.py"', win32=True), 'foo.py')
     nt.assert_equals(path.unquote_filename('"foo bar.py"', win32=True), 'foo bar.py')
     nt.assert_equals(path.unquote_filename("'foo.py'", win32=True), 'foo.py')
     nt.assert_equals(path.unquote_filename("'foo bar.py'", win32=True), 'foo bar.py')
     nt.assert_equals(path.unquote_filename('"foo.py"', win32=False), '"foo.py"')
     nt.assert_equals(path.unquote_filename('"foo bar.py"', win32=False), '"foo bar.py"')
     nt.assert_equals(path.unquote_filename("'foo.py'", win32=False), "'foo.py'")
     nt.assert_equals(path.unquote_filename("'foo bar.py'", win32=False), "'foo bar.py'")
 
 @with_environment
 def test_get_py_filename():
     os.chdir(TMP_TEST_DIR)
     for win32 in (True, False):
         with make_tempfile('foo.py'):
             nt.assert_equals(path.get_py_filename('foo.py', force_win32=win32), 'foo.py')
             nt.assert_equals(path.get_py_filename('foo', force_win32=win32), 'foo.py')
         with make_tempfile('foo'):
             nt.assert_equals(path.get_py_filename('foo', force_win32=win32), 'foo')
             nt.assert_raises(IOError, path.get_py_filename, 'foo.py', force_win32=win32)
         nt.assert_raises(IOError, path.get_py_filename, 'foo', force_win32=win32)
         nt.assert_raises(IOError, path.get_py_filename, 'foo.py', force_win32=win32)
         true_fn = 'foo with spaces.py'
         with make_tempfile(true_fn):
             nt.assert_equals(path.get_py_filename('foo with spaces', force_win32=win32), true_fn)
             nt.assert_equals(path.get_py_filename('foo with spaces.py', force_win32=win32), true_fn)
             if win32:
                 nt.assert_equals(path.get_py_filename('"foo with spaces.py"', force_win32=True), true_fn)
                 nt.assert_equals(path.get_py_filename("'foo with spaces.py'", force_win32=True), true_fn)
             else:
                 nt.assert_raises(IOError, path.get_py_filename, '"foo with spaces.py"', force_win32=False)
                 nt.assert_raises(IOError, path.get_py_filename, "'foo with spaces.py'", force_win32=False)