BF - allow nose with-doctest setting in environment

IPDoctest replaces the normal doctest plugin.  Previously we did this by
initializing the builtin plugins but skipping the doctest plugin.
However, if the user has a noserc file with 'with-doctest=1' or the
environment variable 'NOSE_WITH_DOCTEST', then nose will try and
initialize the doctest plugin when it isn't there, and barf.  This
commit defers the removal of the doctest plugin to the configuration
stage, so doctest can be enabled before it is thrown away by us.

IPython/testing/iptest.py

@@ -1,443 +1,437 b''
 # -*- coding: utf-8 -*-
 """IPython Test Suite Runner.
 
 This module provides a main entry point to a user script to test IPython
 itself from the command line. There are two ways of running this script:
 
 1. With the syntax `iptest all`.  This runs our entire test suite by
    calling this script (with different arguments) recursively.  This
    causes modules and package to be tested in different processes, using nose
    or trial where appropriate.
 2. With the regular nose syntax, like `iptest -vvs IPython`.  In this form
    the script simply calls nose, but with special command line flags and
    plugins loaded.
 
 """
 
 #-----------------------------------------------------------------------------
 #  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
 #-----------------------------------------------------------------------------
 
 # Stdlib
 import os
 import os.path as path
 import signal
 import sys
 import subprocess
 import tempfile
 import time
 import warnings
 
 # Note: monkeypatch!
 # We need to monkeypatch a small problem in nose itself first, before importing
 # it for actual use.  This should get into nose upstream, but its release cycle
 # is slow and we need it for our parametric tests to work correctly.
 from IPython.testing import nosepatch
 # Now, proceed to import nose itself
 import nose.plugins.builtin
 from nose.core import TestProgram
 
 # Our own imports
 from IPython.utils.path import get_ipython_module_path
 from IPython.utils.process import find_cmd, pycmd2argv
 from IPython.utils.sysinfo import sys_info
 
 from IPython.testing import globalipapp
 from IPython.testing.plugin.ipdoctest import IPythonDoctest
 from IPython.external.decorators import KnownFailure
 
 pjoin = path.join
 
 
 #-----------------------------------------------------------------------------
 # Globals
 #-----------------------------------------------------------------------------
 
 
 #-----------------------------------------------------------------------------
 # Warnings control
 #-----------------------------------------------------------------------------
 
 # Twisted generates annoying warnings with Python 2.6, as will do other code
 # that imports 'sets' as of today
 warnings.filterwarnings('ignore', 'the sets module is deprecated',
                         DeprecationWarning )
 
 # This one also comes from Twisted
 warnings.filterwarnings('ignore', 'the sha module is deprecated',
                         DeprecationWarning)
 
 # Wx on Fedora11 spits these out
 warnings.filterwarnings('ignore', 'wxPython/wxWidgets release number mismatch',
                         UserWarning)
 
 #-----------------------------------------------------------------------------
 # Logic for skipping doctests
 #-----------------------------------------------------------------------------
 
 def test_for(mod, min_version=None):
     """Test to see if mod is importable."""
     try:
         __import__(mod)
     except (ImportError, RuntimeError):
         # GTK reports Runtime error if it can't be initialized even if  it's
         # importable.
         return False
     else:
         if min_version:
             return sys.modules[mod].__version__ >= min_version
         else:
             return True
 
 # Global dict where we can store information on what we have and what we don't
 # have available at test run time
 have = {}
 
 have['curses'] = test_for('_curses')
 have['matplotlib'] = test_for('matplotlib')
 have['pexpect'] = test_for('pexpect')
 have['pymongo'] = test_for('pymongo')
 have['wx'] = test_for('wx')
 have['wx.aui'] = test_for('wx.aui')
 if os.name == 'nt':
     have['zmq'] = test_for('zmq', '2.1.7')
 else:
     have['zmq'] = test_for('zmq', '2.1.4')
 have['qt'] = test_for('IPython.external.qt')
 
 #-----------------------------------------------------------------------------
 # Functions and classes
 #-----------------------------------------------------------------------------
 
 def report():
     """Return a string with a summary report of test-related variables."""
 
     out = [ sys_info(), '\n']
 
     avail = []
     not_avail = []
     
     for k, is_avail in have.items():
         if is_avail:
             avail.append(k)
         else:
             not_avail.append(k)
 
     if avail:
         out.append('\nTools and libraries available at test time:\n')
         avail.sort()
         out.append('   ' + ' '.join(avail)+'\n')
 
     if not_avail:
         out.append('\nTools and libraries NOT available at test time:\n')
         not_avail.sort()
         out.append('   ' + ' '.join(not_avail)+'\n')
         
     return ''.join(out)
 
 
 def make_exclude():
     """Make patterns of modules and packages to exclude from testing.
 
     For the IPythonDoctest plugin, we need to exclude certain patterns that
     cause testing problems.  We should strive to minimize the number of
     skipped modules, since this means untested code.
 
     These modules and packages will NOT get scanned by nose at all for tests.
     """
     # Simple utility to make IPython paths more readably, we need a lot of
     # these below
     ipjoin = lambda *paths: pjoin('IPython', *paths)
     
     exclusions = [ipjoin('external'),
                   pjoin('IPython_doctest_plugin'),
                   ipjoin('quarantine'),
                   ipjoin('deathrow'),
                   ipjoin('testing', 'attic'),
                   # This guy is probably attic material
                   ipjoin('testing', 'mkdoctests'),
                   # Testing inputhook will need a lot of thought, to figure out
                   # how to have tests that don't lock up with the gui event
                   # loops in the picture
                   ipjoin('lib', 'inputhook'),
                   # Config files aren't really importable stand-alone
                   ipjoin('config', 'default'),
                   ipjoin('config', 'profile'),
                   ]
 
     if not have['wx']:
         exclusions.append(ipjoin('lib', 'inputhookwx'))
         
     # We do this unconditionally, so that the test suite doesn't import
     # gtk, changing the default encoding and masking some unicode bugs.
     exclusions.append(ipjoin('lib', 'inputhookgtk'))
 
     # These have to be skipped on win32 because the use echo, rm, cd, etc.
     # See ticket https://github.com/ipython/ipython/issues/87
     if sys.platform == 'win32':
         exclusions.append(ipjoin('testing', 'plugin', 'test_exampleip'))
         exclusions.append(ipjoin('testing', 'plugin', 'dtexample'))
 
     if not have['pexpect']:
         exclusions.extend([ipjoin('scripts', 'irunner'),
                            ipjoin('lib', 'irunner'),
                            ipjoin('lib', 'tests', 'test_irunner')])
 
     if not have['zmq']:
         exclusions.append(ipjoin('zmq'))
         exclusions.append(ipjoin('frontend', 'qt'))
         exclusions.append(ipjoin('parallel'))
     elif not have['qt']:
         exclusions.append(ipjoin('frontend', 'qt'))
     
     if not have['pymongo']:
         exclusions.append(ipjoin('parallel', 'controller', 'mongodb'))
         exclusions.append(ipjoin('parallel', 'tests', 'test_mongodb'))
 
     if not have['matplotlib']:
         exclusions.extend([ipjoin('lib', 'pylabtools'),
                            ipjoin('lib', 'tests', 'test_pylabtools')])
 
     # This is needed for the reg-exp to match on win32 in the ipdoctest plugin.
     if sys.platform == 'win32':
         exclusions = [s.replace('\\','\\\\') for s in exclusions]
 
     return exclusions
 
 
 class IPTester(object):
     """Call that calls iptest or trial in a subprocess.
     """
     #: string, name of test runner that will be called
     runner = None
     #: list, parameters for test runner
     params = None
     #: list, arguments of system call to be made to call test runner
     call_args = None
     #: list, process ids of subprocesses we start (for cleanup)
     pids = None
     
     def __init__(self, runner='iptest', params=None):
         """Create new test runner."""
         p = os.path
         if runner == 'iptest':
             iptest_app = get_ipython_module_path('IPython.testing.iptest')
             self.runner = pycmd2argv(iptest_app) + sys.argv[1:]
         else:
             raise Exception('Not a valid test runner: %s' % repr(runner))
         if params is None:
             params = []
         if isinstance(params, str):
             params = [params]
         self.params = params
 
         # Assemble call
         self.call_args = self.runner+self.params
 
         # Store pids of anything we start to clean up on deletion, if possible
         # (on posix only, since win32 has no os.kill)
         self.pids = []
 
     if sys.platform == 'win32':
         def _run_cmd(self):
             # On Windows, use os.system instead of subprocess.call, because I
             # was having problems with subprocess and I just don't know enough
             # about win32 to debug this reliably.  Os.system may be the 'old
             # fashioned' way to do it, but it works just fine.  If someone
             # later can clean this up that's fine, as long as the tests run
             # reliably in win32.
             # What types of problems are you having. They may be related to
             # running Python in unboffered mode. BG.
             return os.system(' '.join(self.call_args))
     else:
         def _run_cmd(self):
             # print >> sys.stderr, '*** CMD:', ' '.join(self.call_args) # dbg
             subp = subprocess.Popen(self.call_args)
             self.pids.append(subp.pid)
             # If this fails, the pid will be left in self.pids and cleaned up
             # later, but if the wait call succeeds, then we can clear the
             # stored pid.
             retcode = subp.wait()
             self.pids.pop()
             return retcode
         
     def run(self):
         """Run the stored commands"""
         try:
             return self._run_cmd()
         except:
             import traceback
             traceback.print_exc()
             return 1  # signal failure
 
     def __del__(self):
         """Cleanup on exit by killing any leftover processes."""
 
         if not hasattr(os, 'kill'):
             return
         
         for pid in self.pids:
             try:
                 print 'Cleaning stale PID:', pid
                 os.kill(pid, signal.SIGKILL)
             except OSError:
                 # This is just a best effort, if we fail or the process was
                 # really gone, ignore it.
                 pass     
 
 
 def make_runners():
     """Define the top-level packages that need to be tested.
     """
 
     # Packages to be tested via nose, that only depend on the stdlib
     nose_pkg_names = ['config', 'core', 'extensions', 'frontend', 'lib',
                      'scripts', 'testing', 'utils' ]
     
     if have['zmq']:
         nose_pkg_names.append('parallel')
     
     # For debugging this code, only load quick stuff
     #nose_pkg_names = ['core', 'extensions']  # dbg
 
     # Make fully qualified package names prepending 'IPython.' to our name lists
     nose_packages = ['IPython.%s' % m for m in nose_pkg_names ]
 
     # Make runners
     runners = [ (v, IPTester('iptest', params=v)) for v in nose_packages ]
     
     return runners
 
 
 def run_iptest():
     """Run the IPython test suite using nose.
     
     This function is called when this script is **not** called with the form
     `iptest all`.  It simply calls nose with appropriate command line flags
     and accepts all of the standard nose arguments.
     """
 
     warnings.filterwarnings('ignore', 
         'This will be removed soon.  Use IPython.testing.util instead')
 
     argv = sys.argv + [ '--detailed-errors',  # extra info in tracebacks
                                                 
                         # Loading ipdoctest causes problems with Twisted, but
                         # our test suite runner now separates things and runs
                         # all Twisted tests with trial.
                         '--with-ipdoctest',
                         '--ipdoctest-tests','--ipdoctest-extension=txt',
                         
                         # We add --exe because of setuptools' imbecility (it
                         # blindly does chmod +x on ALL files).  Nose does the
                         # right thing and it tries to avoid executables,
                         # setuptools unfortunately forces our hand here.  This
                         # has been discussed on the distutils list and the
                         # setuptools devs refuse to fix this problem!
                         '--exe',
                         ]
 
     if nose.__version__ >= '0.11':
         # I don't fully understand why we need this one, but depending on what
         # directory the test suite is run from, if we don't give it, 0 tests
         # get run.  Specifically, if the test suite is run from the source dir
         # with an argument (like 'iptest.py IPython.core', 0 tests are run,
         # even if the same call done in this directory works fine).  It appears
         # that if the requested package is in the current dir, nose bails early
         # by default.  Since it's otherwise harmless, leave it in by default
         # for nose >= 0.11, though unfortunately nose 0.10 doesn't support it.
         argv.append('--traverse-namespace')
 
-    # Construct list of plugins, omitting the existing doctest plugin, which
-    # ours replaces (and extends).
+    # use our plugin for doctesting.  It will remove the standard doctest plugin
+    # if it finds it enabled
     plugins = [IPythonDoctest(make_exclude()), KnownFailure()]
-    for p in nose.plugins.builtin.plugins:
-        plug = p()
-        if plug.name == 'doctest':
-            continue
-        plugins.append(plug)
-
     # We need a global ipython running in this process
     globalipapp.start_ipython()
     # Now nose can run
-    TestProgram(argv=argv, plugins=plugins)
+    TestProgram(argv=argv, addplugins=plugins)
 
 
 def run_iptestall():
     """Run the entire IPython test suite by calling nose and trial.
     
     This function constructs :class:`IPTester` instances for all IPython
     modules and package and then runs each of them.  This causes the modules
     and packages of IPython to be tested each in their own subprocess using
     nose or twisted.trial appropriately.
     """
 
     runners = make_runners()
 
     # Run the test runners in a temporary dir so we can nuke it when finished
     # to clean up any junk files left over by accident.  This also makes it
     # robust against being run in non-writeable directories by mistake, as the
     # temp dir will always be user-writeable.
     curdir = os.getcwdu()
     testdir = tempfile.gettempdir()
     os.chdir(testdir)
 
     # Run all test runners, tracking execution time
     failed = []
     t_start = time.time()
     try:
         for (name, runner) in runners:
             print '*'*70
             print 'IPython test group:',name
             res = runner.run()
             if res:
                 failed.append( (name, runner) )
     finally:
         os.chdir(curdir)
     t_end = time.time()
     t_tests = t_end - t_start
     nrunners = len(runners)
     nfail = len(failed)
     # summarize results
     print
     print '*'*70
     print 'Test suite completed for system with the following information:'
     print report()
     print 'Ran %s test groups in %.3fs' % (nrunners, t_tests)
     print
     print 'Status:'
     if not failed:
         print 'OK'
     else:
         # If anything went wrong, point out what command to rerun manually to
         # see the actual errors and individual summary
         print 'ERROR - %s out of %s test groups failed.' % (nfail, nrunners)
         for name, failed_runner in failed:
             print '-'*40
             print 'Runner failed:',name
             print 'You may wish to rerun this one individually, with:'
             print ' '.join(failed_runner.call_args)
             print
         # Ensure that our exit code indicates failure
         sys.exit(1)
 
 
 def main():
     for arg in sys.argv[1:]:
         if arg.startswith('IPython'):
             # This is in-process
             run_iptest()
     else:
         # This starts subprocesses
         run_iptestall()
 
 
 if __name__ == '__main__':
     main()

IPython/testing/plugin/ipdoctest.py

@@ -1,793 +1,799 b''
 """Nose Plugin that supports IPython doctests.
 
 Limitations:
 
 - When generating examples for use as doctests, make sure that you have
   pretty-printing OFF.  This can be done either by starting ipython with the
   flag '--nopprint', by setting pprint to 0 in your ipythonrc file, or by
   interactively disabling it with %Pprint.  This is required so that IPython
   output matches that of normal Python, which is used by doctest for internal
   execution.
 
 - Do not rely on specific prompt numbers for results (such as using
   '_34==True', for example).  For IPython tests run via an external process the
   prompt numbers may be different, and IPython tests run as normal python code
   won't even have these special _NN variables set at all.
 """
 
 #-----------------------------------------------------------------------------
 # Module imports
 
 # From the standard library
 import __builtin__
 import commands
 import doctest
 import inspect
 import logging
 import os
 import re
 import sys
 import traceback
 import unittest
 
 from inspect import getmodule
 from StringIO import StringIO
 
 # We are overriding the default doctest runner, so we need to import a few
 # things from doctest directly
 from doctest import (REPORTING_FLAGS, REPORT_ONLY_FIRST_FAILURE,
                      _unittest_reportflags, DocTestRunner,
                      _extract_future_flags, pdb, _OutputRedirectingPdb,
                      _exception_traceback,
                      linecache)
 
 # Third-party modules
 import nose.core
 
 from nose.plugins import doctests, Plugin
 from nose.util import anyp, getpackage, test_address, resolve_name, tolist
 
 #-----------------------------------------------------------------------------
 # Module globals and other constants
 #-----------------------------------------------------------------------------
 
 log = logging.getLogger(__name__)
 
 
 #-----------------------------------------------------------------------------
 # Classes and functions
 #-----------------------------------------------------------------------------
 
 def is_extension_module(filename):
     """Return whether the given filename is an extension module.
 
     This simply checks that the extension is either .so or .pyd.
     """
     return os.path.splitext(filename)[1].lower() in ('.so','.pyd')
 
 
 class DocTestSkip(object):
     """Object wrapper for doctests to be skipped."""
     
     ds_skip = """Doctest to skip.
     >>> 1 #doctest: +SKIP
     """
 
     def __init__(self,obj):
         self.obj = obj
 
     def __getattribute__(self,key):
         if key == '__doc__':
             return DocTestSkip.ds_skip
         else:
             return getattr(object.__getattribute__(self,'obj'),key)
 
 # Modified version of the one in the stdlib, that fixes a python bug (doctests
 # not found in extension modules, http://bugs.python.org/issue3158)
 class DocTestFinder(doctest.DocTestFinder):
 
     def _from_module(self, module, object):
         """
         Return true if the given object is defined in the given
         module.
         """
         if module is None:
             return True
         elif inspect.isfunction(object):
             return module.__dict__ is object.func_globals
         elif inspect.isbuiltin(object):
             return module.__name__ == object.__module__
         elif inspect.isclass(object):
             return module.__name__ == object.__module__
         elif inspect.ismethod(object):
             # This one may be a bug in cython that fails to correctly set the
             # __module__ attribute of methods, but since the same error is easy
             # to make by extension code writers, having this safety in place
             # isn't such a bad idea
             return module.__name__ == object.im_class.__module__
         elif inspect.getmodule(object) is not None:
             return module is inspect.getmodule(object)
         elif hasattr(object, '__module__'):
             return module.__name__ == object.__module__
         elif isinstance(object, property):
             return True # [XX] no way not be sure.
         else:
             raise ValueError("object must be a class or function")
 
     def _find(self, tests, obj, name, module, source_lines, globs, seen):
         """
         Find tests for the given object and any contained objects, and
         add them to `tests`.
         """
         #print '_find for:', obj, name, module  # dbg
         if hasattr(obj,"skip_doctest"):
             #print 'SKIPPING DOCTEST FOR:',obj  # dbg
             obj = DocTestSkip(obj)
 
         doctest.DocTestFinder._find(self,tests, obj, name, module,
                                     source_lines, globs, seen)
 
         # Below we re-run pieces of the above method with manual modifications,
         # because the original code is buggy and fails to correctly identify
         # doctests in extension modules.
 
         # Local shorthands
         from inspect import isroutine, isclass, ismodule
 
         # Look for tests in a module's contained objects.
         if inspect.ismodule(obj) and self._recurse:
             for valname, val in obj.__dict__.items():
                 valname1 = '%s.%s' % (name, valname)
                 if ( (isroutine(val) or isclass(val))
                      and self._from_module(module, val) ):
 
                     self._find(tests, val, valname1, module, source_lines,
                                globs, seen)
 
         # Look for tests in a class's contained objects.
         if inspect.isclass(obj) and self._recurse:
             #print 'RECURSE into class:',obj  # dbg
             for valname, val in obj.__dict__.items():
                 # Special handling for staticmethod/classmethod.
                 if isinstance(val, staticmethod):
                     val = getattr(obj, valname)
                 if isinstance(val, classmethod):
                     val = getattr(obj, valname).im_func
 
                 # Recurse to methods, properties, and nested classes.
                 if ((inspect.isfunction(val) or inspect.isclass(val) or
                      inspect.ismethod(val) or
                       isinstance(val, property)) and
                       self._from_module(module, val)):
                     valname = '%s.%s' % (name, valname)
                     self._find(tests, val, valname, module, source_lines,
                                globs, seen)
 
 
 class IPDoctestOutputChecker(doctest.OutputChecker):
     """Second-chance checker with support for random tests.
     
     If the default comparison doesn't pass, this checker looks in the expected
     output string for flags that tell us to ignore the output.
     """
 
     random_re = re.compile(r'#\s*random\s+')
     
     def check_output(self, want, got, optionflags):
         """Check output, accepting special markers embedded in the output.
 
         If the output didn't pass the default validation but the special string
         '#random' is included, we accept it."""
 
         # Let the original tester verify first, in case people have valid tests
         # that happen to have a comment saying '#random' embedded in.
         ret = doctest.OutputChecker.check_output(self, want, got,
                                                  optionflags)
         if not ret and self.random_re.search(want):
             #print >> sys.stderr, 'RANDOM OK:',want  # dbg
             return True
 
         return ret
 
 
 class DocTestCase(doctests.DocTestCase):
     """Proxy for DocTestCase: provides an address() method that
     returns the correct address for the doctest case. Otherwise
     acts as a proxy to the test case. To provide hints for address(),
     an obj may also be passed -- this will be used as the test object
     for purposes of determining the test address, if it is provided.
     """
 
     # Note: this method was taken from numpy's nosetester module.
 
     # Subclass nose.plugins.doctests.DocTestCase to work around a bug in
     # its constructor that blocks non-default arguments from being passed
     # down into doctest.DocTestCase
 
     def __init__(self, test, optionflags=0, setUp=None, tearDown=None,
                  checker=None, obj=None, result_var='_'):
         self._result_var = result_var
         doctests.DocTestCase.__init__(self, test,
                                       optionflags=optionflags,
                                       setUp=setUp, tearDown=tearDown,
                                       checker=checker)
         # Now we must actually copy the original constructor from the stdlib
         # doctest class, because we can't call it directly and a bug in nose
         # means it never gets passed the right arguments.
 
         self._dt_optionflags = optionflags
         self._dt_checker = checker
         self._dt_test = test
         self._dt_test_globs_ori = test.globs
         self._dt_setUp = setUp
         self._dt_tearDown = tearDown
 
         # XXX - store this runner once in the object!
         runner = IPDocTestRunner(optionflags=optionflags,
                                  checker=checker, verbose=False)
         self._dt_runner = runner
 
 
         # Each doctest should remember the directory it was loaded from, so
         # things like %run work without too many contortions
         self._ori_dir = os.path.dirname(test.filename)
 
     # Modified runTest from the default stdlib
     def runTest(self):
         test = self._dt_test
         runner = self._dt_runner
         
         old = sys.stdout
         new = StringIO()
         optionflags = self._dt_optionflags
 
         if not (optionflags & REPORTING_FLAGS):
             # The option flags don't include any reporting flags,
             # so add the default reporting flags
             optionflags |= _unittest_reportflags
 
         try:
             # Save our current directory and switch out to the one where the
             # test was originally created, in case another doctest did a
             # directory change.  We'll restore this in the finally clause.
             curdir = os.getcwdu()
             #print 'runTest in dir:', self._ori_dir  # dbg
             os.chdir(self._ori_dir)
 
             runner.DIVIDER = "-"*70
             failures, tries = runner.run(test,out=new.write,
                                          clear_globs=False)
         finally:
             sys.stdout = old
             os.chdir(curdir)
 
         if failures:
             raise self.failureException(self.format_failure(new.getvalue()))
 
     def setUp(self):
         """Modified test setup that syncs with ipython namespace"""
         #print "setUp test", self._dt_test.examples # dbg
         if isinstance(self._dt_test.examples[0],IPExample):
             # for IPython examples *only*, we swap the globals with the ipython
             # namespace, after updating it with the globals (which doctest
             # fills with the necessary info from the module being tested).
             _ip.user_ns.update(self._dt_test.globs)
             self._dt_test.globs = _ip.user_ns
             # IPython must protect the _ key in the namespace (it can't exist)
             # so that Python's doctest code sets it naturally, so we enable
             # this feature of our testing namespace.
             _ip.user_ns.protect_underscore = True
 
         super(DocTestCase, self).setUp()
 
     def tearDown(self):
 
         # Undo the test.globs reassignment we made, so that the parent class
         # teardown doesn't destroy the ipython namespace
         if isinstance(self._dt_test.examples[0],IPExample):
             self._dt_test.globs = self._dt_test_globs_ori
             # Restore the behavior of the '_' key in the user namespace to
             # normal after each doctest, so that unittests behave normally
             _ip.user_ns.protect_underscore = False
             
         # XXX - fperez: I am not sure if this is truly a bug in nose 0.11, but
         # it does look like one to me: its tearDown method tries to run
         #
         # delattr(__builtin__, self._result_var)
         #
         # without checking that the attribute really is there; it implicitly
         # assumes it should have been set via displayhook.  But if the
         # displayhook was never called, this doesn't necessarily happen.  I
         # haven't been able to find a little self-contained example outside of
         # ipython that would show the problem so I can report it to the nose
         # team, but it does happen a lot in our code.
         #
         # So here, we just protect as narrowly as possible by trapping an
         # attribute error whose message would be the name of self._result_var,
         # and letting any other error propagate.
         try:
             super(DocTestCase, self).tearDown()
         except AttributeError, exc:
             if exc.args[0] != self._result_var:
                 raise
 
 
 # A simple subclassing of the original with a different class name, so we can
 # distinguish and treat differently IPython examples from pure python ones.
 class IPExample(doctest.Example): pass
 
 
 class IPExternalExample(doctest.Example):
     """Doctest examples to be run in an external process."""
 
     def __init__(self, source, want, exc_msg=None, lineno=0, indent=0,
                  options=None):
         # Parent constructor
         doctest.Example.__init__(self,source,want,exc_msg,lineno,indent,options)
 
         # An EXTRA newline is needed to prevent pexpect hangs
         self.source += '\n'
 
 
 class IPDocTestParser(doctest.DocTestParser):
     """
     A class used to parse strings containing doctest examples.
 
     Note: This is a version modified to properly recognize IPython input and
     convert any IPython examples into valid Python ones.
     """
     # This regular expression is used to find doctest examples in a
     # string.  It defines three groups: `source` is the source code
     # (including leading indentation and prompts); `indent` is the
     # indentation of the first (PS1) line of the source code; and
     # `want` is the expected output (including leading indentation).
 
     # Classic Python prompts or default IPython ones
     _PS1_PY = r'>>>'
     _PS2_PY = r'\.\.\.'
 
     _PS1_IP = r'In\ \[\d+\]:'
     _PS2_IP = r'\ \ \ \.\.\.+:'
 
     _RE_TPL = r'''
         # Source consists of a PS1 line followed by zero or more PS2 lines.
         (?P<source>
             (?:^(?P<indent> [ ]*) (?P<ps1> %s) .*)    # PS1 line
             (?:\n           [ ]*  (?P<ps2> %s) .*)*)  # PS2 lines
         \n? # a newline
         # Want consists of any non-blank lines that do not start with PS1.
         (?P<want> (?:(?![ ]*$)    # Not a blank line
                      (?![ ]*%s)   # Not a line starting with PS1
                      (?![ ]*%s)   # Not a line starting with PS2
                      .*$\n?       # But any other line
                   )*)
                   '''
 
     _EXAMPLE_RE_PY = re.compile( _RE_TPL % (_PS1_PY,_PS2_PY,_PS1_PY,_PS2_PY),
                                  re.MULTILINE | re.VERBOSE)
 
     _EXAMPLE_RE_IP = re.compile( _RE_TPL % (_PS1_IP,_PS2_IP,_PS1_IP,_PS2_IP),
                                  re.MULTILINE | re.VERBOSE)
 
     # Mark a test as being fully random.  In this case, we simply append the
     # random marker ('#random') to each individual example's output.  This way
     # we don't need to modify any other code.
     _RANDOM_TEST = re.compile(r'#\s*all-random\s+')
 
     # Mark tests to be executed in an external process - currently unsupported.
     _EXTERNAL_IP = re.compile(r'#\s*ipdoctest:\s*EXTERNAL')
     
     def ip2py(self,source):
         """Convert input IPython source into valid Python."""
         out = []
         newline = out.append
         #print 'IPSRC:\n',source,'\n###'  # dbg
         # The input source must be first stripped of all bracketing whitespace
         # and turned into lines, so it looks to the parser like regular user
         # input
         for lnum,line in enumerate(source.strip().splitlines()):
             newline(_ip.prefilter(line,lnum>0))
         newline('')  # ensure a closing newline, needed by doctest
         #print "PYSRC:", '\n'.join(out)  # dbg
         return '\n'.join(out)
 
     def parse(self, string, name='<string>'):
         """
         Divide the given string into examples and intervening text,
         and return them as a list of alternating Examples and strings.
         Line numbers for the Examples are 0-based.  The optional
         argument `name` is a name identifying this string, and is only
         used for error messages.
         """
 
         #print 'Parse string:\n',string # dbg
 
         string = string.expandtabs()
         # If all lines begin with the same indentation, then strip it.
         min_indent = self._min_indent(string)
         if min_indent > 0:
             string = '\n'.join([l[min_indent:] for l in string.split('\n')])
 
         output = []
         charno, lineno = 0, 0
 
         # We make 'all random' tests by adding the '# random' mark to every
         # block of output in the test.
         if self._RANDOM_TEST.search(string):
             random_marker = '\n# random'
         else:
             random_marker = ''
 
         # Whether to convert the input from ipython to python syntax
         ip2py = False
         # Find all doctest examples in the string.  First, try them as Python
         # examples, then as IPython ones
         terms = list(self._EXAMPLE_RE_PY.finditer(string))
         if terms:
             # Normal Python example
             #print '-'*70  # dbg
             #print 'PyExample, Source:\n',string  # dbg
             #print '-'*70  # dbg
             Example = doctest.Example
         else:
             # It's an ipython example.  Note that IPExamples are run
             # in-process, so their syntax must be turned into valid python.
             # IPExternalExamples are run out-of-process (via pexpect) so they
             # don't need any filtering (a real ipython will be executing them).
             terms = list(self._EXAMPLE_RE_IP.finditer(string))
             if self._EXTERNAL_IP.search(string):
                 #print '-'*70  # dbg
                 #print 'IPExternalExample, Source:\n',string  # dbg
                 #print '-'*70  # dbg
                 Example = IPExternalExample
             else:
                 #print '-'*70  # dbg
                 #print 'IPExample, Source:\n',string  # dbg
                 #print '-'*70  # dbg
                 Example = IPExample
                 ip2py = True
 
         for m in terms:
             # Add the pre-example text to `output`.
             output.append(string[charno:m.start()])
             # Update lineno (lines before this example)
             lineno += string.count('\n', charno, m.start())
             # Extract info from the regexp match.
             (source, options, want, exc_msg) = \
                      self._parse_example(m, name, lineno,ip2py)
 
             # Append the random-output marker (it defaults to empty in most
             # cases, it's only non-empty for 'all-random' tests):
             want += random_marker
                 
             if Example is IPExternalExample:
                 options[doctest.NORMALIZE_WHITESPACE] = True
                 want += '\n'
 
             # Create an Example, and add it to the list.
             if not self._IS_BLANK_OR_COMMENT(source):
                 output.append(Example(source, want, exc_msg,
                                       lineno=lineno,
                                       indent=min_indent+len(m.group('indent')),
                                       options=options))
             # Update lineno (lines inside this example)
             lineno += string.count('\n', m.start(), m.end())
             # Update charno.
             charno = m.end()
         # Add any remaining post-example text to `output`.
         output.append(string[charno:])
         return output
 
     def _parse_example(self, m, name, lineno,ip2py=False):
         """
         Given a regular expression match from `_EXAMPLE_RE` (`m`),
         return a pair `(source, want)`, where `source` is the matched
         example's source code (with prompts and indentation stripped);
         and `want` is the example's expected output (with indentation
         stripped).
 
         `name` is the string's name, and `lineno` is the line number
         where the example starts; both are used for error messages.
 
         Optional:
         `ip2py`: if true, filter the input via IPython to convert the syntax
         into valid python.
         """
 
         # Get the example's indentation level.
         indent = len(m.group('indent'))
 
         # Divide source into lines; check that they're properly
         # indented; and then strip their indentation & prompts.
         source_lines = m.group('source').split('\n')
 
         # We're using variable-length input prompts
         ps1 = m.group('ps1')
         ps2 = m.group('ps2')
         ps1_len = len(ps1)
 
         self._check_prompt_blank(source_lines, indent, name, lineno,ps1_len)
         if ps2:
             self._check_prefix(source_lines[1:], ' '*indent + ps2, name, lineno)
 
         source = '\n'.join([sl[indent+ps1_len+1:] for sl in source_lines])
 
         if ip2py:
             # Convert source input from IPython into valid Python syntax
             source = self.ip2py(source)
 
         # Divide want into lines; check that it's properly indented; and
         # then strip the indentation.  Spaces before the last newline should
         # be preserved, so plain rstrip() isn't good enough.
         want = m.group('want')
         want_lines = want.split('\n')
         if len(want_lines) > 1 and re.match(r' *$', want_lines[-1]):
             del want_lines[-1]  # forget final newline & spaces after it
         self._check_prefix(want_lines, ' '*indent, name,
                            lineno + len(source_lines))
 
         # Remove ipython output prompt that might be present in the first line
         want_lines[0] = re.sub(r'Out\[\d+\]: \s*?\n?','',want_lines[0])
 
         want = '\n'.join([wl[indent:] for wl in want_lines])
 
         # If `want` contains a traceback message, then extract it.
         m = self._EXCEPTION_RE.match(want)
         if m:
             exc_msg = m.group('msg')
         else:
             exc_msg = None
 
         # Extract options from the source.
         options = self._find_options(source, name, lineno)
 
         return source, options, want, exc_msg
 
     def _check_prompt_blank(self, lines, indent, name, lineno, ps1_len):
         """
         Given the lines of a source string (including prompts and
         leading indentation), check to make sure that every prompt is
         followed by a space character.  If any line is not followed by
         a space character, then raise ValueError.
 
         Note: IPython-modified version which takes the input prompt length as a
         parameter, so that prompts of variable length can be dealt with.
         """
         space_idx = indent+ps1_len
         min_len = space_idx+1
         for i, line in enumerate(lines):
             if len(line) >=  min_len and line[space_idx] != ' ':
                 raise ValueError('line %r of the docstring for %s '
                                  'lacks blank after %s: %r' %
                                  (lineno+i+1, name,
                                   line[indent:space_idx], line))
 
 
 SKIP = doctest.register_optionflag('SKIP')
 
 
 class IPDocTestRunner(doctest.DocTestRunner,object):
     """Test runner that synchronizes the IPython namespace with test globals.
     """
     
     def run(self, test, compileflags=None, out=None, clear_globs=True):
 
         # Hack: ipython needs access to the execution context of the example,
         # so that it can propagate user variables loaded by %run into
         # test.globs.  We put them here into our modified %run as a function
         # attribute.  Our new %run will then only make the namespace update
         # when called (rather than unconconditionally updating test.globs here
         # for all examples, most of which won't be calling %run anyway).
         #_ip._ipdoctest_test_globs = test.globs
         #_ip._ipdoctest_test_filename = test.filename
 
         test.globs.update(_ip.user_ns)
         
         return super(IPDocTestRunner,self).run(test,
                                                compileflags,out,clear_globs)
 
 
 class DocFileCase(doctest.DocFileCase):
     """Overrides to provide filename
     """
     def address(self):
         return (self._dt_test.filename, None, None)
 
 
 class ExtensionDoctest(doctests.Doctest):
     """Nose Plugin that supports doctests in extension modules.
     """
     name = 'extdoctest'   # call nosetests with --with-extdoctest
     enabled = True
 
     def __init__(self,exclude_patterns=None):
         """Create a new ExtensionDoctest plugin.
 
         Parameters
         ----------
 
         exclude_patterns : sequence of strings, optional
           These patterns are compiled as regular expressions, subsequently used
           to exclude any filename which matches them from inclusion in the test
           suite (using pattern.search(), NOT pattern.match() ).
         """
 
         if exclude_patterns is None:
             exclude_patterns = []
         self.exclude_patterns = map(re.compile,exclude_patterns)
         doctests.Doctest.__init__(self)
 
     def options(self, parser, env=os.environ):
         Plugin.options(self, parser, env)
         parser.add_option('--doctest-tests', action='store_true',
                           dest='doctest_tests',
                           default=env.get('NOSE_DOCTEST_TESTS',True),
                           help="Also look for doctests in test modules. "
                           "Note that classes, methods and functions should "
                           "have either doctests or non-doctest tests, "
                           "not both. [NOSE_DOCTEST_TESTS]")
         parser.add_option('--doctest-extension', action="append",
                           dest="doctestExtension",
                           help="Also look for doctests in files with "
                           "this extension [NOSE_DOCTEST_EXTENSION]")
         # Set the default as a list, if given in env; otherwise
         # an additional value set on the command line will cause
         # an error.
         env_setting = env.get('NOSE_DOCTEST_EXTENSION')
         if env_setting is not None:
             parser.set_defaults(doctestExtension=tolist(env_setting))
 
 
     def configure(self, options, config):
         Plugin.configure(self, options, config)
+        # Pull standard doctest plugin out of config; we will do doctesting
+        config.plugins.plugins = [p for p in config.plugins.plugins
+                                  if p.name != 'doctest']
         self.doctest_tests = options.doctest_tests
         self.extension = tolist(options.doctestExtension)
 
         self.parser = doctest.DocTestParser()
         self.finder = DocTestFinder()
         self.checker = IPDoctestOutputChecker()
         self.globs = None
         self.extraglobs = None
 
 
     def loadTestsFromExtensionModule(self,filename):
         bpath,mod = os.path.split(filename)
         modname = os.path.splitext(mod)[0]
         try:
             sys.path.append(bpath)
             module = __import__(modname)
             tests = list(self.loadTestsFromModule(module))
         finally:
             sys.path.pop()
         return tests
 
     # NOTE: the method below is almost a copy of the original one in nose, with
     # a  few modifications to control output checking.
 
     def loadTestsFromModule(self, module):
         #print '*** ipdoctest - lTM',module  # dbg
         
         if not self.matches(module.__name__):
             log.debug("Doctest doesn't want module %s", module)
             return
 
         tests = self.finder.find(module,globs=self.globs,
                                  extraglobs=self.extraglobs)
         if not tests:
             return
 
         # always use whitespace and ellipsis options
         optionflags = doctest.NORMALIZE_WHITESPACE | doctest.ELLIPSIS
 
         tests.sort()
         module_file = module.__file__
         if module_file[-4:] in ('.pyc', '.pyo'):
             module_file = module_file[:-1]
         for test in tests:
             if not test.examples:
                 continue
             if not test.filename:
                 test.filename = module_file
             
             yield DocTestCase(test,
                               optionflags=optionflags,
                               checker=self.checker)
 
 
     def loadTestsFromFile(self, filename):
         #print "ipdoctest - from file", filename # dbg
         if is_extension_module(filename):
             for t in self.loadTestsFromExtensionModule(filename):
                 yield t
         else:
             if self.extension and anyp(filename.endswith, self.extension):
                 name = os.path.basename(filename)
                 dh = open(filename)
                 try:
                     doc = dh.read()
                 finally:
                     dh.close()
                 test = self.parser.get_doctest(
                     doc, globs={'__file__': filename}, name=name,
                     filename=filename, lineno=0)
                 if test.examples:
                     #print 'FileCase:',test.examples  # dbg
                     yield DocFileCase(test)
                 else:
                     yield False # no tests to load
 
     def wantFile(self,filename):
         """Return whether the given filename should be scanned for tests.
 
         Modified version that accepts extension modules as valid containers for
         doctests.
         """
         #print '*** ipdoctest- wantFile:',filename  # dbg
 
         for pat in self.exclude_patterns:
             if pat.search(filename):
                 # print '###>>> SKIP:',filename  # dbg
                 return False
 
         if is_extension_module(filename):
             return True
         else:
             return doctests.Doctest.wantFile(self,filename)
 
 
 class IPythonDoctest(ExtensionDoctest):
     """Nose Plugin that supports doctests in extension modules.
     """
     name = 'ipdoctest'   # call nosetests with --with-ipdoctest
     enabled = True
 
     def makeTest(self, obj, parent):
         """Look for doctests in the given object, which will be a
         function, method or class.
         """
         #print 'Plugin analyzing:', obj, parent  # dbg
         # always use whitespace and ellipsis options
         optionflags = doctest.NORMALIZE_WHITESPACE | doctest.ELLIPSIS
 
         doctests = self.finder.find(obj, module=getmodule(parent))
         if doctests:
             for test in doctests:
                 if len(test.examples) == 0:
                     continue
 
                 yield DocTestCase(test, obj=obj,
                                   optionflags=optionflags,
                                   checker=self.checker)
 
     def options(self, parser, env=os.environ):
         #print "Options for nose plugin:", self.name # dbg
         Plugin.options(self, parser, env)
         parser.add_option('--ipdoctest-tests', action='store_true',
                           dest='ipdoctest_tests',
                           default=env.get('NOSE_IPDOCTEST_TESTS',True),
                           help="Also look for doctests in test modules. "
                           "Note that classes, methods and functions should "
                           "have either doctests or non-doctest tests, "
                           "not both. [NOSE_IPDOCTEST_TESTS]")
         parser.add_option('--ipdoctest-extension', action="append",
                           dest="ipdoctest_extension",
                           help="Also look for doctests in files with "
                           "this extension [NOSE_IPDOCTEST_EXTENSION]")
         # Set the default as a list, if given in env; otherwise
         # an additional value set on the command line will cause
         # an error.
         env_setting = env.get('NOSE_IPDOCTEST_EXTENSION')
         if env_setting is not None:
             parser.set_defaults(ipdoctest_extension=tolist(env_setting))
 
     def configure(self, options, config):
         #print "Configuring nose plugin:", self.name # dbg
         Plugin.configure(self, options, config)
+        # Pull standard doctest plugin out of config; we will do doctesting
+        config.plugins.plugins = [p for p in config.plugins.plugins
+                                  if p.name != 'doctest']
         self.doctest_tests = options.ipdoctest_tests
         self.extension = tolist(options.ipdoctest_extension)
 
         self.parser = IPDocTestParser()
         self.finder = DocTestFinder(parser=self.parser)
         self.checker = IPDoctestOutputChecker()
         self.globs = None
         self.extraglobs = None