Correctly implement namespace handling. Minor cleanups.

Finally found a solution to manage the namespace where doctests are
run in conjunction with the IPython one.  All tests seem to pass now
(except for an intermittent failure in one Twisted one that looks like
a race condition somewhere, since it doesn't always appear).

IPython/testing/plugin/Makefile

@@ -1,66 +1,75 b''
 # Set this prefix to where you want to install the plugin
 PREFIX=~/usr/local
 PREFIX=~/tmp/local
 
 NOSE0=nosetests -vs --with-doctest --doctest-tests --detailed-errors
-NOSE=nosetests -vvs --with-ipdoctest --doctest-tests --doctest-extension=txt --detailed-errors
+NOSE=nosetests -vvs --with-ipdoctest --doctest-tests --doctest-extension=txt \
+--detailed-errors
 
 SRC=ipdoctest.py setup.py ../decorators.py
 
 # Default target for clean 'make'
 default: iplib
 
 # The actual plugin installation
 plugin: IPython_doctest_plugin.egg-info
 
 # Simple targets that test one thing
 simple: plugin simple.py
 	$(NOSE) simple.py
 
 dtest: plugin dtexample.py
 	$(NOSE) dtexample.py
 
 rtest: plugin test_refs.py
 	$(NOSE) test_refs.py
 
 test: plugin dtexample.py
 	$(NOSE) dtexample.py test*.py test*.txt
 
 deb: plugin dtexample.py
 	$(NOSE) test_combo.txt
 
 # IPython tests
 deco:
-	$(NOSE0) -x IPython.testing.decorators
+	$(NOSE0) IPython.testing.decorators
 
 magic: plugin
-	$(NOSE) -x IPython.Magic
+	$(NOSE) IPython.Magic
 
 ipipe: plugin
-	$(NOSE) -x IPython.Extensions.ipipe
+	$(NOSE) IPython.Extensions.ipipe
 
 iplib: plugin
-	$(NOSE) -x IPython.iplib
+	$(NOSE)  IPython.iplib
 
 strd: plugin
-	nosetests -vs --with-doctest --doctest-tests IPython.strdispatch
 	$(NOSE) IPython.strdispatch
 
+engine: plugin
+	$(NOSE) IPython.kernel
+
+tf: plugin
+	$(NOSE) IPython.config.traitlets
+
 # All of ipython itself
 ipython: plugin
 	$(NOSE) IPython
 
+
 # Combined targets
 sr: rtest strd
 
 base: dtest rtest test strd deco
 
+quick: base iplib ipipe
+
 all: base ipython
 
 # Main plugin and cleanup
 IPython_doctest_plugin.egg-info: $(SRC)
 	python setup.py install --prefix=$(PREFIX)
 	touch $@
 
 clean:
 	rm -rf IPython_doctest_plugin.egg-info *~ *pyc build/ dist/

IPython/testing/plugin/ipdoctest.py

@@ -1,867 +1,784 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.
-
-- IPython functions that produce output as a side-effect of calling a system
-  process (e.g. 'ls') can be doc-tested, but they must be handled in an
-  external IPython process.  Such doctests must be tagged with:
-
-        # ipdoctest: EXTERNAL
-
-  so that the testing machinery handles them differently.  Since these are run
-  via pexpect in an external process, they can't deal with exceptions or other
-  fancy featurs of regular doctests.  You must limit such tests to simple
-  matching of the output.  For this reason, I recommend you limit these kinds
-  of doctests to features that truly require a separate process, and use the
-  normal IPython ones (which have all the features of normal doctests) for
-  everything else.  See the examples at the bottom of this file for a
-  comparison of what can be done with both types.
 """
 
 
 #-----------------------------------------------------------------------------
 # 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
 
-# Our own imports
-#from extdoctest import ExtensionDoctest, DocTestFinder
-#from dttools import DocTestFinder, DocTestCase
 #-----------------------------------------------------------------------------
 # Module globals and other constants
 
 log = logging.getLogger(__name__)
 
 ###########################################################################
 # *** HACK ***
 # We must start our own ipython object and heavily muck with it so that all the
 # modifications IPython makes to system behavior don't send the doctest
 # machinery into a fit.  This code should be considered a gross hack, but it
 # gets the job done.
 
 
-# XXX - Hack to modify the %run command so we can sync the user's namespace
-# with the test globals.  Once we move over to a clean magic system, this will
-# be done with much less ugliness.
+# Hack to modify the %run command so we can sync the user's namespace with the
+# test globals.  Once we move over to a clean magic system, this will be done
+# with much less ugliness.
 
 def _run_ns_sync(self,arg_s,runner=None):
     """Modified version of %run that syncs testing namespaces.
 
     This is strictly needed for running doctests that call %run.
     """
 
     out = _ip.IP.magic_run_ori(arg_s,runner)
     _run_ns_sync.test_globs.update(_ip.user_ns)
     return out
 
 
-# XXX1 - namespace handling
-class ncdict(dict):
+class ipnsdict(dict):
+    """A special subclass of dict for use as an IPython namespace in doctests.
+
+    This subclass adds a simple checkpointing capability so that when testing
+    machinery clears it (we use it as the test execution context), it doesn't
+    get completely destroyed.
+    """
+    
     def __init__(self,*a):
         dict.__init__(self,*a)
         self._savedict = {}
         
-    def copy(self):
-        return self
-
     def clear(self):
-        import IPython
-        
-        print 'NCDICT - clear'   # dbg
         dict.clear(self)
-        self.update(IPython.ipapi.make_user_ns())
         self.update(self._savedict)
 
-    def remember(self,adict):
-        self._savedict = adict
-    
-#class ncdict(dict): pass
+    def _checkpoint(self):
+        self._savedict.clear()
+        self._savedict.update(self)
+
+    def update(self,other):
+        self._checkpoint()
+        dict.update(self,other)
+        # If '_' is in the namespace, python won't set it when executing code,
+        # and we have examples that test it.  So we ensure that the namespace
+        # is always 'clean' of it before it's used for test code execution.
+        self.pop('_',None)
+        
 
 def start_ipython():
     """Start a global IPython shell, which we need for IPython-specific syntax.
     """
     import new
 
     import IPython
 
     def xsys(cmd):
         """Execute a command and print its output.
 
         This is just a convenience function to replace the IPython system call
         with one that is more doctest-friendly.
         """
         cmd = _ip.IP.var_expand(cmd,depth=1)
         sys.stdout.write(commands.getoutput(cmd))
         sys.stdout.flush()
 
     # Store certain global objects that IPython modifies
     _displayhook = sys.displayhook
     _excepthook = sys.excepthook
     _main = sys.modules.get('__main__')
 
     # Start IPython instance.  We customize it to start with minimal frills.
-    user_ns,global_ns = IPython.ipapi.make_user_namespaces(ncdict(),dict())
+    user_ns,global_ns = IPython.ipapi.make_user_namespaces(ipnsdict(),dict())
     
     IPython.Shell.IPShell(['--classic','--noterm_title'],
                           user_ns,global_ns)
 
     # Deactivate the various python system hooks added by ipython for
     # interactive convenience so we don't confuse the doctest system
     sys.modules['__main__'] = _main
     sys.displayhook = _displayhook
     sys.excepthook = _excepthook
 
     # So that ipython magics and aliases can be doctested (they work by making
     # a call into a global _ip object)
     _ip = IPython.ipapi.get()
     __builtin__._ip = _ip
 
     # Modify the IPython system call with one that uses getoutput, so that we
     # can capture subcommands and print them to Python's stdout, otherwise the
     # doctest machinery would miss them.
     _ip.system = xsys
 
     # Also patch our %run function in.
     im = new.instancemethod(_run_ns_sync,_ip.IP, _ip.IP.__class__)
     _ip.IP.magic_run_ori = _ip.IP.magic_run
     _ip.IP.magic_run = im
 
 # The start call MUST be made here.  I'm not sure yet why it doesn't work if
 # it is made later, at plugin initialization time, but in all my tests, that's
 # the case.
 start_ipython()
 
 # *** END HACK ***
 ###########################################################################
 
 # 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 nodoc(object):
     def __init__(self,obj):
         self.obj = obj
 
     def __getattribute__(self,key):
         if key == '__doc__':
             return None
         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`.
         """
 
         if hasattr(obj,"skip_doctest"):
             #print 'SKIPPING DOCTEST FOR:',obj  # dbg
             obj = nodoc(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)
 
 
-    # XXX1 - namespace handling
-    def Xfind(self, obj, name=None, module=None, globs=None, extraglobs=None):
-        """
-        Return a list of the DocTests that are defined by the given
-        object's docstring, or by any of its contained objects'
-        docstrings.
-
-        The optional parameter `module` is the module that contains
-        the given object.  If the module is not specified or is None, then
-        the test finder will attempt to automatically determine the
-        correct module.  The object's module is used:
-
-            - As a default namespace, if `globs` is not specified.
-            - To prevent the DocTestFinder from extracting DocTests
-              from objects that are imported from other modules.
-            - To find the name of the file containing the object.
-            - To help find the line number of the object within its
-              file.
-
-        Contained objects whose module does not match `module` are ignored.
-
-        If `module` is False, no attempt to find the module will be made.
-        This is obscure, of use mostly in tests:  if `module` is False, or
-        is None but cannot be found automatically, then all objects are
-        considered to belong to the (non-existent) module, so all contained
-        objects will (recursively) be searched for doctests.
-
-        The globals for each DocTest is formed by combining `globs`
-        and `extraglobs` (bindings in `extraglobs` override bindings
-        in `globs`).  A new copy of the globals dictionary is created
-        for each DocTest.  If `globs` is not specified, then it
-        defaults to the module's `__dict__`, if specified, or {}
-        otherwise.  If `extraglobs` is not specified, then it defaults
-        to {}.
-
-        """
-
-        # Find the module that contains the given object (if obj is
-        # a module, then module=obj.).  Note: this may fail, in which
-        # case module will be None.
-        if module is False:
-            module = None
-        elif module is None:
-            module = inspect.getmodule(obj)
-
-        # always build our own globals
-        if globs is None:
-            if module is None:
-                globs = {}
-            else:
-                globs = module.__dict__.copy()
-        else:
-            globs.update(module.__dict__.copy())
-
-        print 'globs is:',globs.keys()
-        
-        if extraglobs is not None:
-            globs.update(extraglobs)
-
-        try:
-            globs.remember(module.__dict__)
-        except:
-            pass
-        
-        ## # Initialize globals, and merge in extraglobs.
-        ## if globs is None:
-        ##     if module is None:
-        ##         globs = {}
-        ##     else:
-        ##         globs = module.__dict__.copy()
-        ## else:
-        ##     globs = globs.copy()
-        ## if extraglobs is not None:
-        ##     globs.update(extraglobs)
-
-        return doctest.DocTestFinder.find(self,obj,name,module,globs,
-                                          extraglobs)
-
-
 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_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 what directory it was loaded from...
         self._ori_dir = os.getcwd()
 
     # 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
 
-        runner = IPDocTestRunner(optionflags=optionflags,
-                                 checker=self._dt_checker, verbose=False)
-
         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.getcwd()
             os.chdir(self._ori_dir)
 
             runner.DIVIDER = "-"*70
-            failures, tries = runner.run(
-                test, out=new.write, clear_globs=False)
+            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()))
 
-    # XXX1 - namespace handling
-    def XtearDown(self):
-        print '!! teardown!'  # dbg
-        doctests.DocTestCase.tearDown(self)
-
+    def setUp(self):
+        """Modified test setup that syncs with ipython namespace"""
+        
+        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.IP.user_ns.update(self._dt_test.globs)
+            self._dt_test.globs = _ip.IP.user_ns
+
+        doctests.DocTestCase.setUp(self)
+    
 
 
 # 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
         for lnum,line in enumerate(source.splitlines()):
             newline(_ip.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).
         _run_ns_sync.test_globs = test.globs
 
-        # dbg
-        ## print >> sys.stderr, "Test:",test
-        ## for ex in test.examples:
-        ##     print >> sys.stderr, ex.source
-        ##     print >> sys.stderr, 'Want:\n',ex.want,'\n--'
-
         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 options(self, parser, env=os.environ):
         Plugin.options(self, parser, env)
 
     def configure(self, options, config):
         Plugin.configure(self, options, config)
         self.doctest_tests = options.doctest_tests
         self.extension = tolist(options.doctestExtension)
-        self.finder = DocTestFinder()
+
         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 '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
-
-            # xxx - checker and options may be ok instantiated once outside loop
-            # always use whitespace and ellipsis options
-            optionflags = doctest.NORMALIZE_WHITESPACE | doctest.ELLIPSIS
-            checker = IPDoctestOutputChecker()
             
             yield DocTestCase(test,
                               optionflags=optionflags,
-                              checker=checker)
+                              checker=self.checker)
+
 
     def loadTestsFromFile(self, filename):
         #print 'lTF',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 'Filename:',filename  # dbg
 
-        # temporarily hardcoded list, will move to driver later
+        # XXX - temporarily hardcoded list, will move to driver later
         exclude = ['IPython/external/',
                    'IPython/Extensions/ipy_',
                    'IPython/platutils_win32',
                    'IPython/frontend/cocoa',
                    'IPython_doctest_plugin',
                    'IPython/Gnuplot',
                    'IPython/Extensions/PhysicalQIn']
 
         for fex in exclude:
             if fex in filename:  # substring
                 #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 configure(self, options, config):
 
         Plugin.configure(self, options, config)
         self.doctest_tests = options.doctest_tests
         self.extension = tolist(options.doctestExtension)
+
         self.parser = IPDocTestParser()
         self.finder = DocTestFinder(parser=self.parser)
-
-        # XXX1 - namespace handling
+        self.checker = IPDoctestOutputChecker()
         self.globs = None
-        #self.globs = _ip.IP.user_ns
-        
         self.extraglobs = None