Remove EventManager reset methods, because they violate encapsulation.

The whole idea of the EventManager is that you can register hooks
without worrying about what hooks other pieces of code might be
registering. The reset methods violate this separation of concerns,
since they will blow away everyone else's hooks too. (See gh-6680 for
an example of this breaking things.) Since there is never any safe way
to use them, we simply remove them entirely.

IPython/core/events.py

@@ -1,139 +1,131 b''
 """Infrastructure for registering and firing callbacks on application events.
 
 Unlike :mod:`IPython.core.hooks`, which lets end users set single functions to
 be called at specific times, or a collection of alternative methods to try,
 callbacks are designed to be used by extension authors. A number of callbacks
 can be registered for the same event without needing to be aware of one another.
 
 The functions defined in this module are no-ops indicating the names of available
 events and the arguments which will be passed to them.
 
 .. note::
 
    This API is experimental in IPython 2.0, and may be revised in future versions.
 """
 from __future__ import print_function
 
 class EventManager(object):
     """Manage a collection of events and a sequence of callbacks for each.
     
     This is attached to :class:`~IPython.core.interactiveshell.InteractiveShell`
     instances as an ``events`` attribute.
     
     .. note::
 
        This API is experimental in IPython 2.0, and may be revised in future versions.
     """
     def __init__(self, shell, available_events):
         """Initialise the :class:`CallbackManager`.
         
         Parameters
         ----------
         shell
           The :class:`~IPython.core.interactiveshell.InteractiveShell` instance
         available_callbacks
           An iterable of names for callback events.
         """
         self.shell = shell
         self.callbacks = {n:[] for n in available_events}
     
     def register(self, event, function):
         """Register a new event callback
         
         Parameters
         ----------
         event : str
           The event for which to register this callback.
         function : callable
           A function to be called on the given event. It should take the same
           parameters as the appropriate callback prototype.
         
         Raises
         ------
         TypeError
           If ``function`` is not callable.
         KeyError
           If ``event`` is not one of the known events.
         """
         if not callable(function):
             raise TypeError('Need a callable, got %r' % function)
         self.callbacks[event].append(function)
     
     def unregister(self, event, function):
         """Remove a callback from the given event."""
         self.callbacks[event].remove(function)
     
-    def reset(self, event):
-        """Clear all callbacks for the given event."""
-        self.callbacks[event] = []
-    
-    def reset_all(self):
-        """Clear all callbacks for all events."""
-        self.callbacks = {n:[] for n in self.callbacks}
-    
     def trigger(self, event, *args, **kwargs):
         """Call callbacks for ``event``.
         
         Any additional arguments are passed to all callbacks registered for this
         event. Exceptions raised by callbacks are caught, and a message printed.
         """
         for func in self.callbacks[event]:
             try:
                 func(*args, **kwargs)
             except Exception:
                 print("Error in callback {} (for {}):".format(func, event))
                 self.shell.showtraceback()
 
 # event_name -> prototype mapping
 available_events = {}
 
 def _define_event(callback_proto):
     available_events[callback_proto.__name__] = callback_proto
     return callback_proto
 
 # ------------------------------------------------------------------------------
 # Callback prototypes
 #
 # No-op functions which describe the names of available events and the
 # signatures of callbacks for those events.
 # ------------------------------------------------------------------------------
 
 @_define_event
 def pre_execute():
     """Fires before code is executed in response to user/frontend action.
     
     This includes comm and widget messages and silent execution, as well as user
     code cells."""
     pass
 
 @_define_event
 def pre_run_cell():
     """Fires before user-entered code runs."""
     pass
 
 @_define_event
 def post_execute():
     """Fires after code is executed in response to user/frontend action.
     
     This includes comm and widget messages and silent execution, as well as user
     code cells."""
     pass
 
 @_define_event
 def post_run_cell():
     """Fires after user-entered code runs."""
     pass
 
 @_define_event
 def shell_initialized(ip):
     """Fires after initialisation of :class:`~IPython.core.interactiveshell.InteractiveShell`.
     
     This is before extensions and startup scripts are loaded, so it can only be
     set by subclassing.
     
     Parameters
     ----------
     ip : :class:`~IPython.core.interactiveshell.InteractiveShell`
       The newly initialised shell.
     """
     pass

IPython/core/tests/test_events.py

@@ -1,46 +1,32 b''
 import unittest
 try:  # Python 3.3 +
     from unittest.mock import Mock
 except ImportError:
     from mock import Mock
 
 from IPython.core import events
 import IPython.testing.tools as tt
 
 def ping_received():
     pass
 
 class CallbackTests(unittest.TestCase):
     def setUp(self):
         self.em = events.EventManager(get_ipython(), {'ping_received': ping_received})
     
     def test_register_unregister(self):
         cb = Mock()
 
         self.em.register('ping_received', cb)        
         self.em.trigger('ping_received')
         self.assertEqual(cb.call_count, 1)
         
         self.em.unregister('ping_received', cb)
         self.em.trigger('ping_received')
         self.assertEqual(cb.call_count, 1)
     
-    def test_reset(self):
-        cb = Mock()
-        self.em.register('ping_received', cb)
-        self.em.reset('ping_received')
-        self.em.trigger('ping_received')
-        assert not cb.called
-    
-    def test_reset_all(self):
-        cb = Mock()
-        self.em.register('ping_received', cb)
-        self.em.reset_all()
-        self.em.trigger('ping_received')
-        assert not cb.called
-    
     def test_cb_error(self):
         cb = Mock(side_effect=ValueError)
         self.em.register('ping_received', cb)
         with tt.AssertPrints("Error in callback"):
-            self.em.trigger('ping_received')
  No newline at end of file
+            self.em.trigger('ping_received')

IPython/core/tests/test_interactiveshell.py

@@ -1,842 +1,845 b''
 # -*- coding: utf-8 -*-
 """Tests for the key interactiveshell module.
 
 Historically the main classes in interactiveshell have been under-tested.  This
 module should grow as many single-method tests as possible to trap many of the
 recurring bugs we seem to encounter with high-level interaction.
 """
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 import ast
 import os
 import signal
 import shutil
 import sys
 import tempfile
 import unittest
 try:
     from unittest import mock
 except ImportError:
     import mock
 from os.path import join
 
 import nose.tools as nt
 
 from IPython.core.error import InputRejected
 from IPython.core.inputtransformer import InputTransformer
 from IPython.testing.decorators import (
     skipif, skip_win32, onlyif_unicode_paths, onlyif_cmds_exist,
 )
 from IPython.testing import tools as tt
 from IPython.utils import io
 from IPython.utils.process import find_cmd
 from IPython.utils import py3compat
 from IPython.utils.py3compat import unicode_type, PY3
 
 if PY3:
     from io import StringIO
 else:
     from StringIO import StringIO
 
 #-----------------------------------------------------------------------------
 # Globals
 #-----------------------------------------------------------------------------
 # This is used by every single test, no point repeating it ad nauseam
 ip = get_ipython()
 
 #-----------------------------------------------------------------------------
 # Tests
 #-----------------------------------------------------------------------------
 
 class InteractiveShellTestCase(unittest.TestCase):
     def test_naked_string_cells(self):
         """Test that cells with only naked strings are fully executed"""
         # First, single-line inputs
         ip.run_cell('"a"\n')
         self.assertEqual(ip.user_ns['_'], 'a')
         # And also multi-line cells
         ip.run_cell('"""a\nb"""\n')
         self.assertEqual(ip.user_ns['_'], 'a\nb')
 
     def test_run_empty_cell(self):
         """Just make sure we don't get a horrible error with a blank
         cell of input. Yes, I did overlook that."""
         old_xc = ip.execution_count
         ip.run_cell('')
         self.assertEqual(ip.execution_count, old_xc)
 
     def test_run_cell_multiline(self):
         """Multi-block, multi-line cells must execute correctly.
         """
         src = '\n'.join(["x=1",
                          "y=2",
                          "if 1:",
                          "    x += 1",
                          "    y += 1",])
         ip.run_cell(src)
         self.assertEqual(ip.user_ns['x'], 2)
         self.assertEqual(ip.user_ns['y'], 3)
 
     def test_multiline_string_cells(self):
         "Code sprinkled with multiline strings should execute (GH-306)"
         ip.run_cell('tmp=0')
         self.assertEqual(ip.user_ns['tmp'], 0)
         ip.run_cell('tmp=1;"""a\nb"""\n')
         self.assertEqual(ip.user_ns['tmp'], 1)
 
     def test_dont_cache_with_semicolon(self):
         "Ending a line with semicolon should not cache the returned object (GH-307)"
         oldlen = len(ip.user_ns['Out'])
         for cell in ['1;', '1;1;']:
             ip.run_cell(cell, store_history=True)
             newlen = len(ip.user_ns['Out'])
             self.assertEqual(oldlen, newlen)
         i = 0
         #also test the default caching behavior
         for cell in ['1', '1;1']:
             ip.run_cell(cell, store_history=True)
             newlen = len(ip.user_ns['Out'])
             i += 1
             self.assertEqual(oldlen+i, newlen)
 
     def test_In_variable(self):
         "Verify that In variable grows with user input (GH-284)"
         oldlen = len(ip.user_ns['In'])
         ip.run_cell('1;', store_history=True)
         newlen = len(ip.user_ns['In'])
         self.assertEqual(oldlen+1, newlen)
         self.assertEqual(ip.user_ns['In'][-1],'1;')
         
     def test_magic_names_in_string(self):
         ip.run_cell('a = """\n%exit\n"""')
         self.assertEqual(ip.user_ns['a'], '\n%exit\n')
     
     def test_trailing_newline(self):
         """test that running !(command) does not raise a SyntaxError"""
         ip.run_cell('!(true)\n', False)
         ip.run_cell('!(true)\n\n\n', False)
     
     def test_gh_597(self):
         """Pretty-printing lists of objects with non-ascii reprs may cause
         problems."""
         class Spam(object):
           def __repr__(self):
             return "\xe9"*50
         import IPython.core.formatters
         f = IPython.core.formatters.PlainTextFormatter()
         f([Spam(),Spam()])
     
 
     def test_future_flags(self):
         """Check that future flags are used for parsing code (gh-777)"""
         ip.run_cell('from __future__ import print_function')
         try:
             ip.run_cell('prfunc_return_val = print(1,2, sep=" ")')
             assert 'prfunc_return_val' in ip.user_ns
         finally:
             # Reset compiler flags so we don't mess up other tests.
             ip.compile.reset_compiler_flags()
 
     def test_future_unicode(self):
         """Check that unicode_literals is imported from __future__ (gh #786)"""
         try:
             ip.run_cell(u'byte_str = "a"')
             assert isinstance(ip.user_ns['byte_str'], str) # string literals are byte strings by default
             ip.run_cell('from __future__ import unicode_literals')
             ip.run_cell(u'unicode_str = "a"')
             assert isinstance(ip.user_ns['unicode_str'], unicode_type) # strings literals are now unicode
         finally:
             # Reset compiler flags so we don't mess up other tests.
             ip.compile.reset_compiler_flags()
     
     def test_can_pickle(self):
         "Can we pickle objects defined interactively (GH-29)"
         ip = get_ipython()
         ip.reset()
         ip.run_cell(("class Mylist(list):\n"
                      "    def __init__(self,x=[]):\n"
                      "        list.__init__(self,x)"))
         ip.run_cell("w=Mylist([1,2,3])")
         
         from pickle import dumps
         
         # We need to swap in our main module - this is only necessary
         # inside the test framework, because IPython puts the interactive module
         # in place (but the test framework undoes this).
         _main = sys.modules['__main__']
         sys.modules['__main__'] = ip.user_module
         try:
             res = dumps(ip.user_ns["w"])
         finally:
             sys.modules['__main__'] = _main
         self.assertTrue(isinstance(res, bytes))
         
     def test_global_ns(self):
         "Code in functions must be able to access variables outside them."
         ip = get_ipython()
         ip.run_cell("a = 10")
         ip.run_cell(("def f(x):\n"
                      "    return x + a"))
         ip.run_cell("b = f(12)")
         self.assertEqual(ip.user_ns["b"], 22)
 
     def test_bad_custom_tb(self):
         """Check that InteractiveShell is protected from bad custom exception handlers"""
         from IPython.utils import io
         save_stderr = io.stderr
         try:
             # capture stderr
             io.stderr = StringIO()
             ip.set_custom_exc((IOError,), lambda etype,value,tb: 1/0)
             self.assertEqual(ip.custom_exceptions, (IOError,))
             ip.run_cell(u'raise IOError("foo")')
             self.assertEqual(ip.custom_exceptions, ())
             self.assertTrue("Custom TB Handler failed" in io.stderr.getvalue())
         finally:
             io.stderr = save_stderr
 
     def test_bad_custom_tb_return(self):
         """Check that InteractiveShell is protected from bad return types in custom exception handlers"""
         from IPython.utils import io
         save_stderr = io.stderr
         try:
             # capture stderr
             io.stderr = StringIO()
             ip.set_custom_exc((NameError,),lambda etype,value,tb, tb_offset=None: 1)
             self.assertEqual(ip.custom_exceptions, (NameError,))
             ip.run_cell(u'a=abracadabra')
             self.assertEqual(ip.custom_exceptions, ())
             self.assertTrue("Custom TB Handler failed" in io.stderr.getvalue())
         finally:
             io.stderr = save_stderr
 
     def test_drop_by_id(self):
         myvars = {"a":object(), "b":object(), "c": object()}
         ip.push(myvars, interactive=False)
         for name in myvars:
             assert name in ip.user_ns, name
             assert name in ip.user_ns_hidden, name
         ip.user_ns['b'] = 12
         ip.drop_by_id(myvars)
         for name in ["a", "c"]:
             assert name not in ip.user_ns, name
             assert name not in ip.user_ns_hidden, name
         assert ip.user_ns['b'] == 12
         ip.reset()
 
     def test_var_expand(self):
         ip.user_ns['f'] = u'Ca\xf1o'
         self.assertEqual(ip.var_expand(u'echo $f'), u'echo Ca\xf1o')
         self.assertEqual(ip.var_expand(u'echo {f}'), u'echo Ca\xf1o')
         self.assertEqual(ip.var_expand(u'echo {f[:-1]}'), u'echo Ca\xf1')
         self.assertEqual(ip.var_expand(u'echo {1*2}'), u'echo 2')
 
         ip.user_ns['f'] = b'Ca\xc3\xb1o'
         # This should not raise any exception:
         ip.var_expand(u'echo $f')
     
     def test_var_expand_local(self):
         """Test local variable expansion in !system and %magic calls"""
         # !system
         ip.run_cell('def test():\n'
                     '    lvar = "ttt"\n'
                     '    ret = !echo {lvar}\n'
                     '    return ret[0]\n')
         res = ip.user_ns['test']()
         nt.assert_in('ttt', res)
         
         # %magic
         ip.run_cell('def makemacro():\n'
                     '    macroname = "macro_var_expand_locals"\n'
                     '    %macro {macroname} codestr\n')
         ip.user_ns['codestr'] = "str(12)"
         ip.run_cell('makemacro()')
         nt.assert_in('macro_var_expand_locals', ip.user_ns)
     
     def test_var_expand_self(self):
         """Test variable expansion with the name 'self', which was failing.
         
         See https://github.com/ipython/ipython/issues/1878#issuecomment-7698218
         """
         ip.run_cell('class cTest:\n'
                     '  classvar="see me"\n'
                     '  def test(self):\n'
                     '    res = !echo Variable: {self.classvar}\n'
                     '    return res[0]\n')
         nt.assert_in('see me', ip.user_ns['cTest']().test())
     
     def test_bad_var_expand(self):
         """var_expand on invalid formats shouldn't raise"""
         # SyntaxError
         self.assertEqual(ip.var_expand(u"{'a':5}"), u"{'a':5}")
         # NameError
         self.assertEqual(ip.var_expand(u"{asdf}"), u"{asdf}")
         # ZeroDivisionError
         self.assertEqual(ip.var_expand(u"{1/0}"), u"{1/0}")
     
     def test_silent_postexec(self):
         """run_cell(silent=True) doesn't invoke pre/post_run_cell callbacks"""
         pre_explicit = mock.Mock()
         pre_always = mock.Mock()
         post_explicit = mock.Mock()
         post_always = mock.Mock()
         
         ip.events.register('pre_run_cell', pre_explicit)
         ip.events.register('pre_execute', pre_always)
         ip.events.register('post_run_cell', post_explicit)
         ip.events.register('post_execute', post_always)
         
         try:
             ip.run_cell("1", silent=True)
             assert pre_always.called
             assert not pre_explicit.called
             assert post_always.called
             assert not post_explicit.called
             # double-check that non-silent exec did what we expected
             # silent to avoid
             ip.run_cell("1")
             assert pre_explicit.called
             assert post_explicit.called
         finally:
             # remove post-exec
-            ip.events.reset_all()
+            ip.events.unregister('pre_run_cell', pre_explicit)
+            ip.events.unregister('pre_execute', pre_always)
+            ip.events.unregister('post_run_cell', post_explicit)
+            ip.events.unregister('post_execute', post_always)
     
     def test_silent_noadvance(self):
         """run_cell(silent=True) doesn't advance execution_count"""
         ec = ip.execution_count
         # silent should force store_history=False
         ip.run_cell("1", store_history=True, silent=True)
         
         self.assertEqual(ec, ip.execution_count)
         # double-check that non-silent exec did what we expected
         # silent to avoid
         ip.run_cell("1", store_history=True)
         self.assertEqual(ec+1, ip.execution_count)
     
     def test_silent_nodisplayhook(self):
         """run_cell(silent=True) doesn't trigger displayhook"""
         d = dict(called=False)
         
         trap = ip.display_trap
         save_hook = trap.hook
         
         def failing_hook(*args, **kwargs):
             d['called'] = True
         
         try:
             trap.hook = failing_hook
             ip.run_cell("1", silent=True)
             self.assertFalse(d['called'])
             # double-check that non-silent exec did what we expected
             # silent to avoid
             ip.run_cell("1")
             self.assertTrue(d['called'])
         finally:
             trap.hook = save_hook
 
     @skipif(sys.version_info[0] >= 3, "softspace removed in py3")
     def test_print_softspace(self):
         """Verify that softspace is handled correctly when executing multiple
         statements.
 
         In [1]: print 1; print 2
         1
         2
 
         In [2]: print 1,; print 2
         1 2
         """
         
     def test_ofind_line_magic(self):
         from IPython.core.magic import register_line_magic
         
         @register_line_magic
         def lmagic(line):
             "A line magic"
 
         # Get info on line magic
         lfind = ip._ofind('lmagic')
         info = dict(found=True, isalias=False, ismagic=True,
                     namespace = 'IPython internal', obj= lmagic.__wrapped__,
                     parent = None)
         nt.assert_equal(lfind, info)
         
     def test_ofind_cell_magic(self):
         from IPython.core.magic import register_cell_magic
         
         @register_cell_magic
         def cmagic(line, cell):
             "A cell magic"
 
         # Get info on cell magic
         find = ip._ofind('cmagic')
         info = dict(found=True, isalias=False, ismagic=True,
                     namespace = 'IPython internal', obj= cmagic.__wrapped__,
                     parent = None)
         nt.assert_equal(find, info)
 
     def test_ofind_property_with_error(self):
         class A(object):
             @property
             def foo(self):
                 raise NotImplementedError()
         a = A()
 
         found = ip._ofind('a.foo', [('locals', locals())])
         info = dict(found=True, isalias=False, ismagic=False,
                     namespace='locals', obj=A.foo, parent=a)
         nt.assert_equal(found, info)
 
     def test_ofind_multiple_attribute_lookups(self):
         class A(object):
             @property
             def foo(self):
                 raise NotImplementedError()
 
         a = A()
         a.a = A()
         a.a.a = A()
 
         found = ip._ofind('a.a.a.foo', [('locals', locals())])
         info = dict(found=True, isalias=False, ismagic=False,
                     namespace='locals', obj=A.foo, parent=a.a.a)
         nt.assert_equal(found, info)
 
     def test_ofind_slotted_attributes(self):
         class A(object):
             __slots__ = ['foo']
             def __init__(self):
                 self.foo = 'bar'
 
         a = A()
         found = ip._ofind('a.foo', [('locals', locals())])
         info = dict(found=True, isalias=False, ismagic=False,
                     namespace='locals', obj=a.foo, parent=a)
         nt.assert_equal(found, info)
 
         found = ip._ofind('a.bar', [('locals', locals())])
         info = dict(found=False, isalias=False, ismagic=False,
                     namespace=None, obj=None, parent=a)
         nt.assert_equal(found, info)
 
     def test_ofind_prefers_property_to_instance_level_attribute(self):
         class A(object):
             @property
             def foo(self):
                 return 'bar'
         a = A()
         a.__dict__['foo'] = 'baz'
         nt.assert_equal(a.foo, 'bar')
         found = ip._ofind('a.foo', [('locals', locals())])
         nt.assert_is(found['obj'], A.foo)
 
     def test_custom_exception(self):
         called = []
         def my_handler(shell, etype, value, tb, tb_offset=None):
             called.append(etype)
             shell.showtraceback((etype, value, tb), tb_offset=tb_offset)
         
         ip.set_custom_exc((ValueError,), my_handler)
         try:
             ip.run_cell("raise ValueError('test')")
             # Check that this was called, and only once.
             self.assertEqual(called, [ValueError])
         finally:
             # Reset the custom exception hook
             ip.set_custom_exc((), None)
     
     @skipif(sys.version_info[0] >= 3, "no differences with __future__ in py3")
     def test_future_environment(self):
         "Can we run code with & without the shell's __future__ imports?"
         ip.run_cell("from __future__ import division")
         ip.run_cell("a = 1/2", shell_futures=True)
         self.assertEqual(ip.user_ns['a'], 0.5)
         ip.run_cell("b = 1/2", shell_futures=False)
         self.assertEqual(ip.user_ns['b'], 0)
         
         ip.compile.reset_compiler_flags()
         # This shouldn't leak to the shell's compiler
         ip.run_cell("from __future__ import division \nc=1/2", shell_futures=False)
         self.assertEqual(ip.user_ns['c'], 0.5)
         ip.run_cell("d = 1/2", shell_futures=True)
         self.assertEqual(ip.user_ns['d'], 0)
 
     def test_mktempfile(self):
         filename = ip.mktempfile()
         # Check that we can open the file again on Windows
         with open(filename, 'w') as f:
             f.write('abc')
 
         filename = ip.mktempfile(data='blah')
         with open(filename, 'r') as f:
             self.assertEqual(f.read(), 'blah')
 
     def test_new_main_mod(self):
         # Smoketest to check that this accepts a unicode module name
         name = u'jiefmw'
         mod = ip.new_main_mod(u'%s.py' % name, name)
         self.assertEqual(mod.__name__, name)
 
 class TestSafeExecfileNonAsciiPath(unittest.TestCase):
 
     @onlyif_unicode_paths
     def setUp(self):
         self.BASETESTDIR = tempfile.mkdtemp()
         self.TESTDIR = join(self.BASETESTDIR, u"åäö")
         os.mkdir(self.TESTDIR)
         with open(join(self.TESTDIR, u"åäötestscript.py"), "w") as sfile:
             sfile.write("pass\n")
         self.oldpath = py3compat.getcwd()
         os.chdir(self.TESTDIR)
         self.fname = u"åäötestscript.py"
 
     def tearDown(self):
         os.chdir(self.oldpath)
         shutil.rmtree(self.BASETESTDIR)
 
     @onlyif_unicode_paths
     def test_1(self):
         """Test safe_execfile with non-ascii path
         """
         ip.safe_execfile(self.fname, {}, raise_exceptions=True)
 
 class ExitCodeChecks(tt.TempFileMixin):
     def test_exit_code_ok(self):
         self.system('exit 0')
         self.assertEqual(ip.user_ns['_exit_code'], 0)
 
     def test_exit_code_error(self):
         self.system('exit 1')
         self.assertEqual(ip.user_ns['_exit_code'], 1)
     
     @skipif(not hasattr(signal, 'SIGALRM'))
     def test_exit_code_signal(self):
         self.mktmp("import signal, time\n"
                    "signal.setitimer(signal.ITIMER_REAL, 0.1)\n"
                    "time.sleep(1)\n")
         self.system("%s %s" % (sys.executable, self.fname))
         self.assertEqual(ip.user_ns['_exit_code'], -signal.SIGALRM)
     
     @onlyif_cmds_exist("csh")
     def test_exit_code_signal_csh(self):
         SHELL = os.environ.get('SHELL', None)
         os.environ['SHELL'] = find_cmd("csh")
         try:
             self.test_exit_code_signal()
         finally:
             if SHELL is not None:
                 os.environ['SHELL'] = SHELL
             else:
                 del os.environ['SHELL']
 
 class TestSystemRaw(unittest.TestCase, ExitCodeChecks):
     system = ip.system_raw
 
     @onlyif_unicode_paths
     def test_1(self):
         """Test system_raw with non-ascii cmd
         """
         cmd = u'''python -c "'åäö'"   '''
         ip.system_raw(cmd)
 
 # TODO: Exit codes are currently ignored on Windows.
 class TestSystemPipedExitCode(unittest.TestCase, ExitCodeChecks):
     system = ip.system_piped
 
     @skip_win32
     def test_exit_code_ok(self):
         ExitCodeChecks.test_exit_code_ok(self)
 
     @skip_win32
     def test_exit_code_error(self):
         ExitCodeChecks.test_exit_code_error(self)
 
     @skip_win32
     def test_exit_code_signal(self):
         ExitCodeChecks.test_exit_code_signal(self)
 
 class TestModules(unittest.TestCase, tt.TempFileMixin):
     def test_extraneous_loads(self):
         """Test we're not loading modules on startup that we shouldn't.
         """
         self.mktmp("import sys\n"
                    "print('numpy' in sys.modules)\n"
                    "print('IPython.parallel' in sys.modules)\n"
                    "print('IPython.kernel.zmq' in sys.modules)\n"
                    )
         out = "False\nFalse\nFalse\n"
         tt.ipexec_validate(self.fname, out)
 
 class Negator(ast.NodeTransformer):
     """Negates all number literals in an AST."""
     def visit_Num(self, node):
         node.n = -node.n
         return node
 
 class TestAstTransform(unittest.TestCase):
     def setUp(self):
         self.negator = Negator()
         ip.ast_transformers.append(self.negator)
     
     def tearDown(self):
         ip.ast_transformers.remove(self.negator)
     
     def test_run_cell(self):
         with tt.AssertPrints('-34'):
             ip.run_cell('print (12 + 22)')
         
         # A named reference to a number shouldn't be transformed.
         ip.user_ns['n'] = 55
         with tt.AssertNotPrints('-55'):
             ip.run_cell('print (n)')
     
     def test_timeit(self):
         called = set()
         def f(x):
             called.add(x)
         ip.push({'f':f})
         
         with tt.AssertPrints("best of "):
             ip.run_line_magic("timeit", "-n1 f(1)")
         self.assertEqual(called, set([-1]))
         called.clear()
         
         with tt.AssertPrints("best of "):
             ip.run_cell_magic("timeit", "-n1 f(2)", "f(3)")
         self.assertEqual(called, set([-2, -3]))
     
     def test_time(self):
         called = []
         def f(x):
             called.append(x)
         ip.push({'f':f})
         
         # Test with an expression
         with tt.AssertPrints("Wall time: "):
             ip.run_line_magic("time", "f(5+9)")
         self.assertEqual(called, [-14])
         called[:] = []
         
         # Test with a statement (different code path)
         with tt.AssertPrints("Wall time: "):
             ip.run_line_magic("time", "a = f(-3 + -2)")
         self.assertEqual(called, [5])
     
     def test_macro(self):
         ip.push({'a':10})
         # The AST transformation makes this do a+=-1
         ip.define_macro("amacro", "a+=1\nprint(a)")
         
         with tt.AssertPrints("9"):
             ip.run_cell("amacro")
         with tt.AssertPrints("8"):
             ip.run_cell("amacro")
 
 class IntegerWrapper(ast.NodeTransformer):
     """Wraps all integers in a call to Integer()"""
     def visit_Num(self, node):
         if isinstance(node.n, int):
             return ast.Call(func=ast.Name(id='Integer', ctx=ast.Load()),
                             args=[node], keywords=[])
         return node
 
 class TestAstTransform2(unittest.TestCase):
     def setUp(self):
         self.intwrapper = IntegerWrapper()
         ip.ast_transformers.append(self.intwrapper)
         
         self.calls = []
         def Integer(*args):
             self.calls.append(args)
             return args
         ip.push({"Integer": Integer})
     
     def tearDown(self):
         ip.ast_transformers.remove(self.intwrapper)
         del ip.user_ns['Integer']
     
     def test_run_cell(self):
         ip.run_cell("n = 2")
         self.assertEqual(self.calls, [(2,)])
         
         # This shouldn't throw an error
         ip.run_cell("o = 2.0")
         self.assertEqual(ip.user_ns['o'], 2.0)
     
     def test_timeit(self):
         called = set()
         def f(x):
             called.add(x)
         ip.push({'f':f})
         
         with tt.AssertPrints("best of "):
             ip.run_line_magic("timeit", "-n1 f(1)")
         self.assertEqual(called, set([(1,)]))
         called.clear()
         
         with tt.AssertPrints("best of "):
             ip.run_cell_magic("timeit", "-n1 f(2)", "f(3)")
         self.assertEqual(called, set([(2,), (3,)]))
 
 class ErrorTransformer(ast.NodeTransformer):
     """Throws an error when it sees a number."""
     def visit_Num(self, node):
         raise ValueError("test")
 
 class TestAstTransformError(unittest.TestCase):
     def test_unregistering(self):
         err_transformer = ErrorTransformer()
         ip.ast_transformers.append(err_transformer)
         
         with tt.AssertPrints("unregister", channel='stderr'):
             ip.run_cell("1 + 2")
         
         # This should have been removed.
         nt.assert_not_in(err_transformer, ip.ast_transformers)
 
 
 class StringRejector(ast.NodeTransformer):
     """Throws an InputRejected when it sees a string literal.
 
     Used to verify that NodeTransformers can signal that a piece of code should
     not be executed by throwing an InputRejected.
     """
 
     def visit_Str(self, node):
         raise InputRejected("test")
 
 
 class TestAstTransformInputRejection(unittest.TestCase):
 
     def setUp(self):
         self.transformer = StringRejector()
         ip.ast_transformers.append(self.transformer)
 
     def tearDown(self):
         ip.ast_transformers.remove(self.transformer)
 
     def test_input_rejection(self):
         """Check that NodeTransformers can reject input."""
 
         expect_exception_tb = tt.AssertPrints("InputRejected: test")
         expect_no_cell_output = tt.AssertNotPrints("'unsafe'", suppress=False)
 
         # Run the same check twice to verify that the transformer is not
         # disabled after raising.
         with expect_exception_tb, expect_no_cell_output:
             ip.run_cell("'unsafe'")
 
         with expect_exception_tb, expect_no_cell_output:
             ip.run_cell("'unsafe'")
 
 def test__IPYTHON__():
     # This shouldn't raise a NameError, that's all
     __IPYTHON__
 
 
 class DummyRepr(object):
     def __repr__(self):
         return "DummyRepr"
     
     def _repr_html_(self):
         return "<b>dummy</b>"
     
     def _repr_javascript_(self):
         return "console.log('hi');", {'key': 'value'}
     
 
 def test_user_variables():
     # enable all formatters
     ip.display_formatter.active_types = ip.display_formatter.format_types
     
     ip.user_ns['dummy'] = d = DummyRepr()
     keys = set(['dummy', 'doesnotexist'])
     r = ip.user_expressions({ key:key for key in keys})
 
     nt.assert_equal(keys, set(r.keys()))
     dummy = r['dummy']
     nt.assert_equal(set(['status', 'data', 'metadata']), set(dummy.keys()))
     nt.assert_equal(dummy['status'], 'ok')
     data = dummy['data']
     metadata = dummy['metadata']
     nt.assert_equal(data.get('text/html'), d._repr_html_())
     js, jsmd = d._repr_javascript_()
     nt.assert_equal(data.get('application/javascript'), js)
     nt.assert_equal(metadata.get('application/javascript'), jsmd)
     
     dne = r['doesnotexist']
     nt.assert_equal(dne['status'], 'error')
     nt.assert_equal(dne['ename'], 'NameError')
     
     # back to text only
     ip.display_formatter.active_types = ['text/plain']
     
 def test_user_expression():
     # enable all formatters
     ip.display_formatter.active_types = ip.display_formatter.format_types
     query = {
         'a' : '1 + 2',
         'b' : '1/0',
     }
     r = ip.user_expressions(query)
     import pprint
     pprint.pprint(r)
     nt.assert_equal(set(r.keys()), set(query.keys()))
     a = r['a']
     nt.assert_equal(set(['status', 'data', 'metadata']), set(a.keys()))
     nt.assert_equal(a['status'], 'ok')
     data = a['data']
     metadata = a['metadata']
     nt.assert_equal(data.get('text/plain'), '3')
     
     b = r['b']
     nt.assert_equal(b['status'], 'error')
     nt.assert_equal(b['ename'], 'ZeroDivisionError')
     
     # back to text only
     ip.display_formatter.active_types = ['text/plain']
     
 
 
 
 
 class TestSyntaxErrorTransformer(unittest.TestCase):
     """Check that SyntaxError raised by an input transformer is handled by run_cell()"""
 
     class SyntaxErrorTransformer(InputTransformer):
 
         def push(self, line):
             pos = line.find('syntaxerror')
             if pos >= 0:
                 e = SyntaxError('input contains "syntaxerror"')
                 e.text = line
                 e.offset = pos + 1
                 raise e
             return line
 
         def reset(self):
             pass
 
     def setUp(self):
         self.transformer = TestSyntaxErrorTransformer.SyntaxErrorTransformer()
         ip.input_splitter.python_line_transforms.append(self.transformer)
         ip.input_transformer_manager.python_line_transforms.append(self.transformer)
 
     def tearDown(self):
         ip.input_splitter.python_line_transforms.remove(self.transformer)
         ip.input_transformer_manager.python_line_transforms.remove(self.transformer)
 
     def test_syntaxerror_input_transformer(self):
         with tt.AssertPrints('1234'):
             ip.run_cell('1234')
         with tt.AssertPrints('SyntaxError: invalid syntax'):
             ip.run_cell('1 2 3')   # plain python syntax error
         with tt.AssertPrints('SyntaxError: input contains "syntaxerror"'):
             ip.run_cell('2345  # syntaxerror')  # input transformer syntax error
         with tt.AssertPrints('3456'):
             ip.run_cell('3456')