text: """ Python test discovery, setup and run of test functions. """
  import fnmatch
  import py
  import inspect
  import sys
  import pytest
  from _pytest.mark import MarkDecorator, MarkerError
  from py._code.code import TerminalRepr
  
  import _pytest
  cutdir = py.path.local(_pytest.__file__).dirpath()
  
  NoneType = type(None)
  NOTSET = object()
  isfunction = inspect.isfunction
  isclass = inspect.isclass
  callable = py.builtin.callable
  # used to work around a python2 exception info leak
  exc_clear = getattr(sys, 'exc_clear', lambda: None)
  
  def getfslineno(obj):
      # xxx let decorators etc specify a sane ordering
      while hasattr(obj, "__wrapped__"):
          obj = obj.__wrapped__
      if hasattr(obj, 'place_as'):
          obj = obj.place_as
      fslineno = py.code.getfslineno(obj)
      assert isinstance(fslineno[1], int), obj
      return fslineno
  
  def getimfunc(func):
      try:
          return func.__func__
      except AttributeError:
          try:
              return func.im_func
          except AttributeError:
              return func
  
  
  class FixtureFunctionMarker:
      def __init__(self, scope, params,
                   autouse=False, yieldctx=False, ids=None):
          self.scope = scope
          self.params = params
          self.autouse = autouse
          self.yieldctx = yieldctx
          self.ids = ids
  
      def __call__(self, function):
          if isclass(function):
              raise ValueError(
                      "class fixtures not supported (may be in the future)")
          function._pytestfixturefunction = self
          return function
  
  
  def fixture(scope="function", params=None, autouse=False, ids=None):
      """ (return a) decorator to mark a fixture factory function.
  
      This decorator can be used (with or or without parameters) to define
      a fixture function.  The name of the fixture function can later be
      referenced to cause its invocation ahead of running tests: test
      modules or classes can use the pytest.mark.usefixtures(fixturename)
      marker.  Test functions can directly use fixture names as input
      arguments in which case the fixture instance returned from the fixture
      function will be injected.
  
      :arg scope: the scope for which this fixture is shared, one of
                  "function" (default), "class", "module", "session".
  
      :arg params: an optional list of parameters which will cause multiple
                  invocations of the fixture function and all of the tests
                  using it.
  
      :arg autouse: if True, the fixture func is activated for all tests that
                  can see it.  If False (the default) then an explicit
                  reference is needed to activate the fixture.
  
      :arg ids: list of string ids each corresponding to the params
         so that they are part of the test id. If no ids are provided
         they will be generated automatically from the params.
  
      """
      if callable(scope) and params is None and autouse == False:
          # direct decoration
          return FixtureFunctionMarker(
                  "function", params, autouse)(scope)
      if params is not None and not isinstance(params, (list, tuple)):
          params = list(params)
      return FixtureFunctionMarker(scope, params, autouse, ids=ids)
  
  def yield_fixture(scope="function", params=None, autouse=False, ids=None):
      """ (return a) decorator to mark a yield-fixture factory function
      (EXPERIMENTAL).
  
      This takes the same arguments as :py:func:`pytest.fixture` but
      expects a fixture function to use a ``yield`` instead of a ``return``
      statement to provide a fixture.  See
      http://pytest.org/en/latest/yieldfixture.html for more info.
      """
      if callable(scope) and params is None and autouse == False:
          # direct decoration
          return FixtureFunctionMarker(
                  "function", params, autouse, yieldctx=True)(scope)
      else:
          return FixtureFunctionMarker(scope, params, autouse,
                                       yieldctx=True, ids=ids)
  
  defaultfuncargprefixmarker = fixture()
  
  def pyobj_property(name):
      def get(self):
          node = self.getparent(getattr(pytest, name))
          if node is not None:
              return node.obj
      doc = "python %s object this node was collected from (can be None)." % (
            name.lower(),)
      return property(get, None, None, doc)
  
  
  def pytest_addoption(parser):
      group = parser.getgroup("general")
      group.addoption('--fixtures', '--funcargs',
                 action="store_true", dest="showfixtures", default=False,
                 help="show available fixtures, sorted by plugin appearance")
      parser.addini("usefixtures", type="args", default=[],
          help="list of default fixtures to be used with this project")
      parser.addini("python_files", type="args",
          default=['test_*.py', '*_test.py'],
          help="glob-style file patterns for Python test module discovery")
      parser.addini("python_classes", type="args", default=["Test",],
          help="prefixes or glob names for Python test class discovery")
      parser.addini("python_functions", type="args", default=["test",],
          help="prefixes or glob names for Python test function and "
               "method discovery")
  
  def pytest_cmdline_main(config):
      if config.option.showfixtures:
          showfixtures(config)
          return 0
  
  
  def pytest_generate_tests(metafunc):
      # this misspelling is common - raise a specific error to alert the user
      if hasattr(metafunc.function, 'parameterize'):
          msg = "{0} has 'parameterize', spelling should be 'parametrize'"
          raise MarkerError(msg.format(metafunc.function.__name__))
      try:
          markers = metafunc.function.parametrize
      except AttributeError:
          return
      for marker in markers:
          metafunc.parametrize(*marker.args, **marker.kwargs)
  
  def pytest_configure(config):
      config.addinivalue_line("markers",
          "parametrize(argnames, argvalues): call a test function multiple "
          "times passing in different arguments in turn. argvalues generally "
          "needs to be a list of values if argnames specifies only one name "
          "or a list of tuples of values if argnames specifies multiple names. "
          "Example: @parametrize('arg1', [1,2]) would lead to two calls of the "
          "decorated test function, one with arg1=1 and another with arg1=2."
          "see http://pytest.org/latest/parametrize.html for more info and "
          "examples."
      )
      config.addinivalue_line("markers",
          "usefixtures(fixturename1, fixturename2, ...): mark tests as needing "
          "all of the specified fixtures. see http://pytest.org/latest/fixture.html#usefixtures "
      )
  
  def pytest_sessionstart(session):
      session._fixturemanager = FixtureManager(session)
  
  @pytest.mark.trylast
  def pytest_namespace():
      raises.Exception = pytest.fail.Exception
      return {
          'fixture': fixture,
          'yield_fixture': yield_fixture,
          'raises' : raises,
          'collect': {
          'Module': Module, 'Class': Class, 'Instance': Instance,
          'Function': Function, 'Generator': Generator,
          '_fillfuncargs': fillfixtures}
      }
  
  @fixture(scope="session")
  def pytestconfig(request):
      """ the pytest config object with access to command line opts."""
      return request.config
  
  
  @pytest.mark.trylast
  def pytest_pyfunc_call(pyfuncitem):
      testfunction = pyfuncitem.obj
      if pyfuncitem._isyieldedfunction():
          testfunction(*pyfuncitem._args)
      else:
          funcargs = pyfuncitem.funcargs
          testargs = {}
          for arg in pyfuncitem._fixtureinfo.argnames:
              testargs[arg] = funcargs[arg]
          testfunction(**testargs)
      return True
  
  def pytest_collect_file(path, parent):
      ext = path.ext
      if ext == ".py":
          if not parent.session.isinitpath(path):
              for pat in parent.config.getini('python_files'):
                  if path.fnmatch(pat):
                      break
              else:
                 return
          ihook = parent.session.gethookproxy(path)
          return ihook.pytest_pycollect_makemodule(path=path, parent=parent)
  
  def pytest_pycollect_makemodule(path, parent):
      return Module(path, parent)
  
  @pytest.mark.hookwrapper
  def pytest_pycollect_makeitem(collector, name, obj):
      outcome = yield
      res = outcome.get_result()
      if res is not None:
          raise StopIteration
      # nothing was collected elsewhere, let's do it here
      if isclass(obj):
          if collector.classnamefilter(name):
              Class = collector._getcustomclass("Class")
              outcome.force_result(Class(name, parent=collector))
      elif collector.funcnamefilter(name) and hasattr(obj, "__call__") and\
          getfixturemarker(obj) is None:
          # mock seems to store unbound methods (issue473), normalize it
          obj = getattr(obj, "__func__", obj)
          if not isfunction(obj):
              collector.warn(code="C2", message=
                  "cannot collect %r because it is not a function."
                  % name, )
          if getattr(obj, "__test__", True):
              if is_generator(obj):
                  res = Generator(name, parent=collector)
              else:
                  res = list(collector._genfunctions(name, obj))
              outcome.force_result(res)
  
  def is_generator(func):
      try:
          return py.code.getrawcode(func).co_flags & 32 # generator function
      except AttributeError: # builtin functions have no bytecode
          # assume them to not be generators
          return False
  
  class PyobjContext(object):
      module = pyobj_property("Module")
      cls = pyobj_property("Class")
      instance = pyobj_property("Instance")
  
  class PyobjMixin(PyobjContext):
      def obj():
          def fget(self):
              try:
                  return self._obj
              except AttributeError:
                  self._obj = obj = self._getobj()
                  return obj
          def fset(self, value):
              self._obj = value
          return property(fget, fset, None, "underlying python object")
      obj = obj()
  
      def _getobj(self):
          return getattr(self.parent.obj, self.name)
  
      def getmodpath(self, stopatmodule=True, includemodule=False):
          """ return python path relative to the containing module. """
          chain = self.listchain()
          chain.reverse()
          parts = []
          for node in chain:
              if isinstance(node, Instance):
                  continue
              name = node.name
              if isinstance(node, Module):
                  assert name.endswith(".py")
                  name = name[:-3]
                  if stopatmodule:
                      if includemodule:
                          parts.append(name)
                      break
              parts.append(name)
          parts.reverse()
          s = ".".join(parts)
          return s.replace(".[", "[")
  
      def _getfslineno(self):
          return getfslineno(self.obj)
  
      def reportinfo(self):
          # XXX caching?
          obj = self.obj
          if hasattr(obj, 'compat_co_firstlineno'):
              # nose compatibility
              fspath = sys.modules[obj.__module__].__file__
              if fspath.endswith(".pyc"):
                  fspath = fspath[:-1]
              lineno = obj.compat_co_firstlineno
          else:
              fspath, lineno = getfslineno(obj)
          modpath = self.getmodpath()
          assert isinstance(lineno, int)
          return fspath, lineno, modpath
  
  class PyCollector(PyobjMixin, pytest.Collector):
  
      def funcnamefilter(self, name):
          return self._matches_prefix_or_glob_option('python_functions', name)
  
      def classnamefilter(self, name):
          return self._matches_prefix_or_glob_option('python_classes', name)
  
      def _matches_prefix_or_glob_option(self, option_name, name):
          """
          checks if the given name matches the prefix or glob-pattern defined
          in ini configuration.
          """
          for option in self.config.getini(option_name):
              if name.startswith(option):
                  return True
              # check that name looks like a glob-string before calling fnmatch
              # because this is called for every name in each collected module,
              # and fnmatch is somewhat expensive to call
              elif ('*' in option or '?' in option or '[' in option) and \
                      fnmatch.fnmatch(name, option):
                  return True
          return False
  
      def collect(self):
          if not getattr(self.obj, "__test__", True):
              return []
  
          # NB. we avoid random getattrs and peek in the __dict__ instead
          # (XXX originally introduced from a PyPy need, still true?)
          dicts = [getattr(self.obj, '__dict__', {})]
          for basecls in inspect.getmro(self.obj.__class__):
              dicts.append(basecls.__dict__)
          seen = {}
          l = []
          for dic in dicts:
              for name, obj in dic.items():
                  if name in seen:
                      continue
                  seen[name] = True
                  res = self.makeitem(name, obj)
                  if res is None:
                      continue
                  if not isinstance(res, list):
                      res = [res]
                  l.extend(res)
          l.sort(key=lambda item: item.reportinfo()[:2])
          return l
  
      def makeitem(self, name, obj):
          #assert self.ihook.fspath == self.fspath, self
          return self.ihook.pytest_pycollect_makeitem(
              collector=self, name=name, obj=obj)
  
      def _genfunctions(self, name, funcobj):
          module = self.getparent(Module).obj
          clscol = self.getparent(Class)
          cls = clscol and clscol.obj or None
          transfer_markers(funcobj, cls, module)
          fm = self.session._fixturemanager
          fixtureinfo = fm.getfixtureinfo(self, funcobj, cls)
          metafunc = Metafunc(funcobj, fixtureinfo, self.config,
                              cls=cls, module=module)
          try:
              methods = [module.pytest_generate_tests]
          except AttributeError:
              methods = []
          if hasattr(cls, "pytest_generate_tests"):
              methods.append(cls().pytest_generate_tests)
          self.ihook.pytest_generate_tests.callextra(methods, metafunc=metafunc)
  
          Function = self._getcustomclass("Function")
          if not metafunc._calls:
              yield Function(name, parent=self, fixtureinfo=fixtureinfo)
          else:
              # add funcargs() as fixturedefs to fixtureinfo.arg2fixturedefs
              add_funcarg_pseudo_fixture_def(self, metafunc, fm)
  
              for callspec in metafunc._calls:
                  subname = "%s[%s]" %(name, callspec.id)
                  yield Function(name=subname, parent=self,
                                 callspec=callspec, callobj=funcobj,
                                 fixtureinfo=fixtureinfo,
                                 keywords={callspec.id:True})
  
  def add_funcarg_pseudo_fixture_def(collector, metafunc, fixturemanager):
      # this function will transform all collected calls to a functions
      # if they use direct funcargs (i.e. direct parametrization)
      # because we want later test execution to be able to rely on
      # an existing FixtureDef structure for all arguments.
      # XXX we can probably avoid this algorithm  if we modify CallSpec2
      # to directly care for creating the fixturedefs within its methods.
      if not metafunc._calls[0].funcargs:
          return # this function call does not have direct parametrization
      # collect funcargs of all callspecs into a list of values
      arg2params = {}
      arg2scope = {}
      for callspec in metafunc._calls:
          for argname, argvalue in callspec.funcargs.items():
              assert argname not in callspec.params
              callspec.params[argname] = argvalue
              arg2params_list = arg2params.setdefault(argname, [])
              callspec.indices[argname] = len(arg2params_list)
              arg2params_list.append(argvalue)
              if argname not in arg2scope:
                  scopenum = callspec._arg2scopenum.get(argname,
                                                        scopenum_function)
                  arg2scope[argname] = scopes[scopenum]
          callspec.funcargs.clear()
  
      # register artificial FixtureDef's so that later at test execution
      # time we can rely on a proper FixtureDef to exist for fixture setup.
      arg2fixturedefs = metafunc._arg2fixturedefs
      for argname, valuelist in arg2params.items():
          # if we have a scope that is higher than function we need
          # to make sure we only ever create an according fixturedef on
          # a per-scope basis. We thus store and cache the fixturedef on the
          # node related to the scope.
          scope = arg2scope[argname]
          node = None
          if scope != "function":
              node = get_scope_node(collector, scope)
              if node is None:
                  assert scope == "class" and isinstance(collector, Module)
                  # use module-level collector for class-scope (for now)
                  node = collector
          if node and argname in node._name2pseudofixturedef:
              arg2fixturedefs[argname] = [node._name2pseudofixturedef[argname]]
          else:
              fixturedef =  FixtureDef(fixturemanager, '', argname,
                             get_direct_param_fixture_func,
                             arg2scope[argname],
                             valuelist, False, False)
              arg2fixturedefs[argname] = [fixturedef]
              if node is not None:
                  node._name2pseudofixturedef[argname] = fixturedef
  
  
  def get_direct_param_fixture_func(request):
      return request.param
  
  class FuncFixtureInfo:
      def __init__(self, argnames, names_closure, name2fixturedefs):
          self.argnames = argnames
          self.names_closure = names_closure
          self.name2fixturedefs = name2fixturedefs
  
  def transfer_markers(funcobj, cls, mod):
      # XXX this should rather be code in the mark plugin or the mark
      # plugin should merge with the python plugin.
      for holder in (cls, mod):
          try:
              pytestmark = holder.pytestmark
          except AttributeError:
              continue
          if isinstance(pytestmark, list):
              for mark in pytestmark:
                  mark(funcobj)
          else:
              pytestmark(funcobj)
  
  class Module(pytest.File, PyCollector):
      """ Collector for test classes and functions. """
      def _getobj(self):
          return self._memoizedcall('_obj', self._importtestmodule)
  
      def collect(self):
          self.session._fixturemanager.parsefactories(self)
          return super(Module, self).collect()
  
      def _importtestmodule(self):
          # we assume we are only called once per module
          try:
              mod = self.fspath.pyimport(ensuresyspath=True)
          except SyntaxError:
              raise self.CollectError(
                  py.code.ExceptionInfo().getrepr(style="short"))
          except self.fspath.ImportMismatchError:
              e = sys.exc_info()[1]
              raise self.CollectError(
                  "import file mismatch:\n"
                  "imported module %r has this __file__ attribute:\n"
                  "  %s\n"
                  "which is not the same as the test file we want to collect:\n"
                  "  %s\n"
                  "HINT: remove __pycache__ / .pyc files and/or use a "
                  "unique basename for your test file modules"
                   % e.args
              )
          #print "imported test module", mod
          self.config.pluginmanager.consider_module(mod)
          return mod
  
      def setup(self):
          setup_module = xunitsetup(self.obj, "setUpModule")
          if setup_module is None:
              setup_module = xunitsetup(self.obj, "setup_module")
          if setup_module is not None:
              #XXX: nose compat hack, move to nose plugin
              # if it takes a positional arg, its probably a pytest style one
              # so we pass the current module object
              if inspect.getargspec(setup_module)[0]:
                  setup_module(self.obj)
              else:
                  setup_module()
          fin = getattr(self.obj, 'tearDownModule', None)
          if fin is None:
              fin = getattr(self.obj, 'teardown_module', None)
          if fin is not None:
              #XXX: nose compat hack, move to nose plugin
              # if it takes a positional arg, it's probably a pytest style one
              # so we pass the current module object
              if inspect.getargspec(fin)[0]:
                  finalizer = lambda: fin(self.obj)
              else:
                  finalizer = fin
              self.addfinalizer(finalizer)
  
  
  class Class(PyCollector):
      """ Collector for test methods. """
      def collect(self):
          if hasinit(self.obj):
              self.warn("C1", "cannot collect test class %r because it has a "
                  "__init__ constructor" % self.obj.__name__)
              return []
          return [self._getcustomclass("Instance")(name="()", parent=self)]
  
      def setup(self):
          setup_class = xunitsetup(self.obj, 'setup_class')
          if setup_class is not None:
              setup_class = getattr(setup_class, 'im_func', setup_class)
              setup_class = getattr(setup_class, '__func__', setup_class)
              setup_class(self.obj)
  
          fin_class = getattr(self.obj, 'teardown_class', None)
          if fin_class is not None:
              fin_class = getattr(fin_class, 'im_func', fin_class)
              fin_class = getattr(fin_class, '__func__', fin_class)
              self.addfinalizer(lambda: fin_class(self.obj))
  
  class Instance(PyCollector):
      def _getobj(self):
          obj = self.parent.obj()
          return obj
  
      def collect(self):
          self.session._fixturemanager.parsefactories(self)
          return super(Instance, self).collect()
  
      def newinstance(self):
          self.obj = self._getobj()
          return self.obj
  
  class FunctionMixin(PyobjMixin):
      """ mixin for the code common to Function and Generator.
      """
  
      def setup(self):
          """ perform setup for this test function. """
          if hasattr(self, '_preservedparent'):
              obj = self._preservedparent
          elif isinstance(self.parent, Instance):
              obj = self.parent.newinstance()
              self.obj = self._getobj()
          else:
              obj = self.parent.obj
          if inspect.ismethod(self.obj):
              setup_name = 'setup_method'
              teardown_name = 'teardown_method'
          else:
              setup_name = 'setup_function'
              teardown_name = 'teardown_function'
          setup_func_or_method = xunitsetup(obj, setup_name)
          if setup_func_or_method is not None:
              setup_func_or_method(self.obj)
          fin = getattr(obj, teardown_name, None)
          if fin is not None:
              self.addfinalizer(lambda: fin(self.obj))
  
      def _prunetraceback(self, excinfo):
          if hasattr(self, '_obj') and not self.config.option.fulltrace:
              code = py.code.Code(self.obj)
              path, firstlineno = code.path, code.firstlineno
              traceback = excinfo.traceback
              ntraceback = traceback.cut(path=path, firstlineno=firstlineno)
              if ntraceback == traceback:
                  ntraceback = ntraceback.cut(path=path)
                  if ntraceback == traceback:
                      ntraceback = ntraceback.cut(excludepath=cutdir)
              excinfo.traceback = ntraceback.filter()
              # issue364: mark all but first and last frames to
              # only show a single-line message for each frame
              if self.config.option.tbstyle == "auto":
                  if len(excinfo.traceback) > 2:
                      for entry in excinfo.traceback[1:-1]:
                          entry.set_repr_style('short')
  
      def _repr_failure_py(self, excinfo, style="long"):
          if excinfo.errisinstance(pytest.fail.Exception):
              if not excinfo.value.pytrace:
                  return str(excinfo.value)
          return super(FunctionMixin, self)._repr_failure_py(excinfo,
              style=style)
  
      def repr_failure(self, excinfo, outerr=None):
          assert outerr is None, "XXX outerr usage is deprecated"
          style = self.config.option.tbstyle
          if style == "auto":
              style = "long"
          return self._repr_failure_py(excinfo, style=style)
  
  
  class Generator(FunctionMixin, PyCollector):
      def collect(self):
          # test generators are seen as collectors but they also
          # invoke setup/teardown on popular request
          # (induced by the common "test_*" naming shared with normal tests)
          self.session._setupstate.prepare(self)
          # see FunctionMixin.setup and test_setupstate_is_preserved_134
          self._preservedparent = self.parent.obj
          l = []
          seen = {}
          for i, x in enumerate(self.obj()):
              name, call, args = self.getcallargs(x)
              if not callable(call):
                  raise TypeError("%r yielded non callable test %r" %(self.obj, call,))
              if name is None:
                  name = "[%d]" % i
              else:
                  name = "['%s']" % name
              if name in seen:
                  raise ValueError("%r generated tests with non-unique name %r" %(self, name))
              seen[name] = True
              l.append(self.Function(name, self, args=args, callobj=call))
          return l
  
      def getcallargs(self, obj):
          if not isinstance(obj, (tuple, list)):
              obj = (obj,)
          # explict naming
          if isinstance(obj[0], py.builtin._basestring):
              name = obj[0]
              obj = obj[1:]
          else:
              name = None
          call, args = obj[0], obj[1:]
          return name, call, args
  
  
  def hasinit(obj):
      init = getattr(obj, '__init__', None)
      if init:
          if init != object.__init__:
              return True
  
  
  
  def fillfixtures(function):
      """ fill missing funcargs for a test function. """
      try:
          request = function._request
      except AttributeError:
          # XXX this special code path is only expected to execute
          # with the oejskit plugin.  It uses classes with funcargs
          # and we thus have to work a bit to allow this.
          fm = function.session._fixturemanager
          fi = fm.getfixtureinfo(function.parent, function.obj, None)
          function._fixtureinfo = fi
          request = function._request = FixtureRequest(function)
          request._fillfixtures()
          # prune out funcargs for jstests
          newfuncargs = {}
          for name in fi.argnames:
              newfuncargs[name] = function.funcargs[name]
          function.funcargs = newfuncargs
      else:
          request._fillfixtures()
  
  
  _notexists = object()
  
  class CallSpec2(object):
      def __init__(self, metafunc):
          self.metafunc = metafunc
          self.funcargs = {}
          self._idlist = []
          self.params = {}
          self._globalid = _notexists
          self._globalid_args = set()
          self._globalparam = _notexists
          self._arg2scopenum = {}  # used for sorting parametrized resources
          self.keywords = {}
          self.indices = {}
  
      def copy(self, metafunc):
          cs = CallSpec2(self.metafunc)
          cs.funcargs.update(self.funcargs)
          cs.params.update(self.params)
          cs.keywords.update(self.keywords)
          cs.indices.update(self.indices)
          cs._arg2scopenum.update(self._arg2scopenum)
          cs._idlist = list(self._idlist)
          cs._globalid = self._globalid
          cs._globalid_args = self._globalid_args
          cs._globalparam = self._globalparam
          return cs
  
      def _checkargnotcontained(self, arg):
          if arg in self.params or arg in self.funcargs:
              raise ValueError("duplicate %r" %(arg,))
  
      def getparam(self, name):
          try:
              return self.params[name]
          except KeyError:
              if self._globalparam is _notexists:
                  raise ValueError(name)
              return self._globalparam
  
      @property
      def id(self):
          return "-".join(map(str, filter(None, self._idlist)))
  
      def setmulti(self, valtype, argnames, valset, id, keywords, scopenum,
                   param_index):
          for arg,val in zip(argnames, valset):
              self._checkargnotcontained(arg)
              getattr(self, valtype)[arg] = val
              self.indices[arg] = param_index
              self._arg2scopenum[arg] = scopenum
              if val is _notexists:
                  self._emptyparamspecified = True
          self._idlist.append(id)
          self.keywords.update(keywords)
  
      def setall(self, funcargs, id, param):
          for x in funcargs:
              self._checkargnotcontained(x)
          self.funcargs.update(funcargs)
          if id is not _notexists:
              self._idlist.append(id)
          if param is not _notexists:
              assert self._globalparam is _notexists
              self._globalparam = param
          for arg in funcargs:
              self._arg2scopenum[arg] = scopenum_function
  
  
  class FuncargnamesCompatAttr:
      """ helper class so that Metafunc, Function and FixtureRequest
      don't need to each define the "funcargnames" compatibility attribute.
      """
      @property
      def funcargnames(self):
          """ alias attribute for ``fixturenames`` for pre-2.3 compatibility"""
          return self.fixturenames
  
  class Metafunc(FuncargnamesCompatAttr):
      def __init__(self, function, fixtureinfo, config, cls=None, module=None):
          self.config = config
          self.module = module
          self.function = function
          self.fixturenames = fixtureinfo.names_closure
          self._arg2fixturedefs = fixtureinfo.name2fixturedefs
          self.cls = cls
          self._calls = []
          self._ids = py.builtin.set()
  
      def parametrize(self, argnames, argvalues, indirect=False, ids=None,
          scope=None):
          """ Add new invocations to the underlying test function using the list
          of argvalues for the given argnames.  Parametrization is performed
          during the collection phase.  If you need to setup expensive resources
          see about setting indirect=True to do it rather at test setup time.
  
          :arg argnames: a comma-separated string denoting one or more argument
                         names, or a list/tuple of argument strings.
  
          :arg argvalues: The list of argvalues determines how often a
              test is invoked with different argument values.  If only one
              argname was specified argvalues is a list of simple values.  If N
              argnames were specified, argvalues must be a list of N-tuples,
              where each tuple-element specifies a value for its respective
              argname.
  
          :arg indirect: if True each argvalue corresponding to an argname will
              be passed as request.param to its respective argname fixture
              function so that it can perform more expensive setups during the
              setup phase of a test rather than at collection time.
  
          :arg ids: list of string ids, or a callable.
              If strings, each is corresponding to the argvalues so that they are
              part of the test id.
              If callable, it should take one argument (a single argvalue) and return
              a string or return None. If None, the automatically generated id for that
              argument will be used.
              If no ids are provided they will be generated automatically from
              the argvalues.
  
          :arg scope: if specified it denotes the scope of the parameters.
              The scope is used for grouping tests by parameter instances.
              It will also override any fixture-function defined scope, allowing
              to set a dynamic scope using test context or configuration.
          """
  
          # individual parametrized argument sets can be wrapped in a series
          # of markers in which case we unwrap the values and apply the mark
          # at Function init
          newkeywords = {}
          unwrapped_argvalues = []
          for i, argval in enumerate(argvalues):
              while isinstance(argval, MarkDecorator):
                  newmark = MarkDecorator(argval.markname,
                                          argval.args[:-1], argval.kwargs)
                  newmarks = newkeywords.setdefault(i, {})
                  newmarks[newmark.markname] = newmark
                  argval = argval.args[-1]
              unwrapped_argvalues.append(argval)
          argvalues = unwrapped_argvalues
  
          if not isinstance(argnames, (tuple, list)):
              argnames = [x.strip() for x in argnames.split(",") if x.strip()]
              if len(argnames) == 1:
                  argvalues = [(val,) for val in argvalues]
          if not argvalues:
              argvalues = [(_notexists,) * len(argnames)]
  
          if scope is None:
              scope = "function"
          scopenum = scopes.index(scope)
          if not indirect:
              #XXX should we also check for the opposite case?
              for arg in argnames:
                  if arg not in self.fixturenames:
                      raise ValueError("%r uses no fixture %r" %(
                                       self.function, arg))
          valtype = indirect and "params" or "funcargs"
          idfn = None
          if callable(ids):
              idfn = ids
              ids = None
          if ids and len(ids) != len(argvalues):
              raise ValueError('%d tests specified with %d ids' %(
                               len(argvalues), len(ids)))
          if not ids:
              ids = idmaker(argnames, argvalues, idfn)
          newcalls = []
          for callspec in self._calls or [CallSpec2(self)]:
              for param_index, valset in enumerate(argvalues):
                  assert len(valset) == len(argnames)
                  newcallspec = callspec.copy(self)
                  newcallspec.setmulti(valtype, argnames, valset, ids[param_index],
                                       newkeywords.get(param_index, {}), scopenum,
                                       param_index)
                  newcalls.append(newcallspec)
          self._calls = newcalls
  
      def addcall(self, funcargs=None, id=_notexists, param=_notexists):
          """ (deprecated, use parametrize) Add a new call to the underlying
          test function during the collection phase of a test run.  Note that
          request.addcall() is called during the test collection phase prior and
          independently to actual test execution.  You should only use addcall()
          if you need to specify multiple arguments of a test function.
  
          :arg funcargs: argument keyword dictionary used when invoking
              the test function.
  
          :arg id: used for reporting and identification purposes.  If you
              don't supply an `id` an automatic unique id will be generated.
  
          :arg param: a parameter which will be exposed to a later fixture function
              invocation through the ``request.param`` attribute.
          """
          assert funcargs is None or isinstance(funcargs, dict)
          if funcargs is not None:
              for name in funcargs:
                  if name not in self.fixturenames:
                      pytest.fail("funcarg %r not used in this function." % name)
          else:
              funcargs = {}
          if id is None:
              raise ValueError("id=None not allowed")
          if id is _notexists:
              id = len(self._calls)
          id = str(id)
          if id in self._ids:
              raise ValueError("duplicate id %r" % id)
          self._ids.add(id)
  
          cs = CallSpec2(self)
          cs.setall(funcargs, id, param)
          self._calls.append(cs)
  
  
  def _idval(val, argname, idx, idfn):
      if idfn:
          try:
              s = idfn(val)
              if s:
                  return s
          except Exception:
              pass
      if isinstance(val, (float, int, str, bool, NoneType)):
          return str(val)
      return str(argname)+str(idx)
  
  def _idvalset(idx, valset, argnames, idfn):
      this_id = [_idval(val, argname, idx, idfn)
                 for val, argname in zip(valset, argnames)]
      return "-".join(this_id)
  
  def idmaker(argnames, argvalues, idfn=None):
      ids = [_idvalset(valindex, valset, argnames, idfn)
             for valindex, valset in enumerate(argvalues)]
      if len(set(ids)) < len(ids):
          # user may have provided a bad idfn which means the ids are not unique
          ids = [str(i) + testid for i, testid in enumerate(ids)]
      return ids
  
  def showfixtures(config):
      from _pytest.main import wrap_session
      return wrap_session(config, _showfixtures_main)
  
  def _showfixtures_main(config, session):
      session.perform_collect()
      curdir = py.path.local()
      if session.items:
          nodeid = session.items[0].nodeid
      else:
          part = session._initialparts[0]
          nodeid = "::".join(map(str, [curdir.bestrelpath(part[0])] + part[1:]))
          nodeid.replace(session.fspath.sep, "/")
  
      tw = py.io.TerminalWriter()
      verbose = config.getvalue("verbose")
  
      fm = session._fixturemanager
  
      available = []
      for argname in fm._arg2fixturedefs:
          fixturedefs = fm.getfixturedefs(argname, nodeid)
          assert fixturedefs is not None
          if not fixturedefs:
              continue
          fixturedef = fixturedefs[-1]
          loc = getlocation(fixturedef.func, curdir)
          available.append((len(fixturedef.baseid),
                            fixturedef.func.__module__,
                            curdir.bestrelpath(loc),
                            fixturedef.argname, fixturedef))
  
      available.sort()
      currentmodule = None
      for baseid, module, bestrel, argname, fixturedef in available:
          if currentmodule != module:
              if not module.startswith("_pytest."):
                  tw.line()
                  tw.sep("-", "fixtures defined from %s" %(module,))
                  currentmodule = module
          if verbose <= 0 and argname[0] == "_":
              continue
          if verbose > 0:
              funcargspec = "%s -- %s" %(argname, bestrel,)
          else:
              funcargspec = argname
          tw.line(funcargspec, green=True)
          loc = getlocation(fixturedef.func, curdir)
          doc = fixturedef.func.__doc__ or ""
          if doc:
              for line in doc.strip().split("\n"):
                  tw.line("    " + line.strip())
          else:
              tw.line("    %s: no docstring available" %(loc,),
                  red=True)
  
  def getlocation(function, curdir):
      import inspect
      fn = py.path.local(inspect.getfile(function))
      lineno = py.builtin._getcode(function).co_firstlineno
      if fn.relto(curdir):
          fn = fn.relto(curdir)
      return "%s:%d" %(fn, lineno+1)
  
  # builtin pytest.raises helper
  
  def raises(ExpectedException, *args, **kwargs):
      """ assert that a code block/function call raises @ExpectedException
      and raise a failure exception otherwise.
  
      This helper produces a ``py.code.ExceptionInfo()`` object.
  
      If using Python 2.5 or above, you may use this function as a
      context manager::
  
          >>> with raises(ZeroDivisionError):
          ...    1/0
  
      Or you can specify a callable by passing a to-be-called lambda::
  
          >>> raises(ZeroDivisionError, lambda: 1/0)
          <ExceptionInfo ...>
  
      or you can specify an arbitrary callable with arguments::
  
          >>> def f(x): return 1/x
          ...
          >>> raises(ZeroDivisionError, f, 0)
          <ExceptionInfo ...>
          >>> raises(ZeroDivisionError, f, x=0)
          <ExceptionInfo ...>
  
      A third possibility is to use a string to be executed::
  
          >>> raises(ZeroDivisionError, "f(0)")
          <ExceptionInfo ...>
  
      Performance note:
      -----------------
  
      Similar to caught exception objects in Python, explicitly clearing
      local references to returned ``py.code.ExceptionInfo`` objects can
      help the Python interpreter speed up its garbage collection.
  
      Clearing those references breaks a reference cycle
      (``ExceptionInfo`` --> caught exception --> frame stack raising
      the exception --> current frame stack --> local variables -->
      ``ExceptionInfo``) which makes Python keep all objects referenced
      from that cycle (including all local variables in the current
      frame) alive until the next cyclic garbage collection run. See the
      official Python ``try`` statement documentation for more detailed
      information.
  
      """
      __tracebackhide__ = True
      if ExpectedException is AssertionError:
          # we want to catch a AssertionError
          # replace our subclass with the builtin one
          # see https://bitbucket.org/pytest-dev/pytest/issue/176/pytestraises
          from _pytest.assertion.util import BuiltinAssertionError \
              as ExpectedException
      msg = ("exceptions must be old-style classes or"
             " derived from BaseException, not %s")
      if isinstance(ExpectedException, tuple):
          for exc in ExpectedException:
              if not inspect.isclass(exc):
                  raise TypeError(msg % type(exc))
      elif not inspect.isclass(ExpectedException):
          raise TypeError(msg % type(ExpectedException))
  
      if not args:
          return RaisesContext(ExpectedException)
      elif isinstance(args[0], str):
          code, = args
          assert isinstance(code, str)
          frame = sys._getframe(1)
          loc = frame.f_locals.copy()
          loc.update(kwargs)
          #print "raises frame scope: %r" % frame.f_locals
          try:
              code = py.code.Source(code).compile()
              py.builtin.exec_(code, frame.f_globals, loc)
              # XXX didn'T mean f_globals == f_locals something special?
              #     this is destroyed here ...
          except ExpectedException:
              return py.code.ExceptionInfo()
      else:
          func = args[0]
          try:
              func(*args[1:], **kwargs)
          except ExpectedException:
              return py.code.ExceptionInfo()
      pytest.fail("DID NOT RAISE")
  
  class RaisesContext(object):
      def __init__(self, ExpectedException):
          self.ExpectedException = ExpectedException
          self.excinfo = None
  
      def __enter__(self):
          self.excinfo = object.__new__(py.code.ExceptionInfo)
          return self.excinfo
  
      def __exit__(self, *tp):
          __tracebackhide__ = True
          if tp[0] is None:
              pytest.fail("DID NOT RAISE")
          self.excinfo.__init__(tp)
          return issubclass(self.excinfo.type, self.ExpectedException)
  
  #
  #  the basic pytest Function item
  #
  
  class Function(FunctionMixin, pytest.Item, FuncargnamesCompatAttr):
      """ a Function Item is responsible for setting up and executing a
      Python test function.
      """
      _genid = None
      def __init__(self, name, parent, args=None, config=None,
                   callspec=None, callobj=NOTSET, keywords=None, session=None,
                   fixtureinfo=None):
          super(Function, self).__init__(name, parent, config=config,
                                         session=session)
          self._args = args
          if callobj is not NOTSET:
              self.obj = callobj
  
          self.keywords.update(self.obj.__dict__)
          if callspec:
              self.callspec = callspec
              self.keywords.update(callspec.keywords)
          if keywords:
              self.keywords.update(keywords)
  
          if fixtureinfo is None:
              fixtureinfo = self.session._fixturemanager.getfixtureinfo(
                  self.parent, self.obj, self.cls,
                  funcargs=not self._isyieldedfunction())
          self._fixtureinfo = fixtureinfo
          self.fixturenames = fixtureinfo.names_closure
          self._initrequest()
  
      def _initrequest(self):
          self.funcargs = {}
          if self._isyieldedfunction():
              assert not hasattr(self, "callspec"), (
                  "yielded functions (deprecated) cannot have funcargs")
          else:
              if hasattr(self, "callspec"):
                  callspec = self.callspec
                  assert not callspec.funcargs
                  self._genid = callspec.id
                  if hasattr(callspec, "param"):
                      self.param = callspec.param
          self._request = FixtureRequest(self)
  
      @property
      def function(self):
          "underlying python 'function' object"
          return getattr(self.obj, 'im_func', self.obj)
  
      def _getobj(self):
          name = self.name
          i = name.find("[") # parametrization
          if i != -1:
              name = name[:i]
          return getattr(self.parent.obj, name)
  
      @property
      def _pyfuncitem(self):
          "(compatonly) for code expecting pytest-2.2 style request objects"
          return self
  
      def _isyieldedfunction(self):
          return getattr(self, "_args", None) is not None
  
      def runtest(self):
          """ execute the underlying test function. """
          self.ihook.pytest_pyfunc_call(pyfuncitem=self)
  
      def setup(self):
          # check if parametrization happend with an empty list
          try:
              self.callspec._emptyparamspecified
          except AttributeError:
              pass
          else:
              fs, lineno = self._getfslineno()
              pytest.skip("got empty parameter set, function %s at %s:%d" %(
                  self.function.__name__, fs, lineno))
          super(Function, self).setup()
          fillfixtures(self)
  
  
  scope2props = dict(session=())
  scope2props["module"] = ("fspath", "module")
  scope2props["class"] = scope2props["module"] + ("cls",)
  scope2props["instance"] = scope2props["class"] + ("instance", )
  scope2props["function"] = scope2props["instance"] + ("function", "keywords")
  
  def scopeproperty(name=None, doc=None):
      def decoratescope(func):
          scopename = name or func.__name__
          def provide(self):
              if func.__name__ in scope2props[self.scope]:
                  return func(self)
              raise AttributeError("%s not available in %s-scoped context" % (
                  scopename, self.scope))
          return property(provide, None, None, func.__doc__)
      return decoratescope
  
  
  class FixtureRequest(FuncargnamesCompatAttr):
      """ A request for a fixture from a test or fixture function.
  
      A request object gives access to the requesting test context
      and has an optional ``param`` attribute in case
      the fixture is parametrized indirectly.
      """
  
      def __init__(self, pyfuncitem):
          self._pyfuncitem = pyfuncitem
          #: fixture for which this request is being performed
          self.fixturename = None
          #: Scope string, one of "function", "cls", "module", "session"
          self.scope = "function"
          self._funcargs  = {}
          self._fixturedefs = {}
          fixtureinfo = pyfuncitem._fixtureinfo
          self._arg2fixturedefs = fixtureinfo.name2fixturedefs.copy()
          self._arg2index = {}
          self.fixturenames = fixtureinfo.names_closure
          self._fixturemanager = pyfuncitem.session._fixturemanager
  
      @property
      def node(self):
          """ underlying collection node (depends on current request scope)"""
          return self._getscopeitem(self.scope)
  
  
      def _getnextfixturedef(self, argname):
          fixturedefs = self._arg2fixturedefs.get(argname, None)
          if fixturedefs is None:
              # we arrive here because of a  a dynamic call to
              # getfuncargvalue(argname) usage which was naturally
              # not known at parsing/collection time
              fixturedefs = self._fixturemanager.getfixturedefs(
                              argname, self._pyfuncitem.parent.nodeid)
              self._arg2fixturedefs[argname] = fixturedefs
          # fixturedefs list is immutable so we maintain a decreasing index
          index = self._arg2index.get(argname, 0) - 1
          if fixturedefs is None or (-index > len(fixturedefs)):
              raise FixtureLookupError(argname, self)
          self._arg2index[argname] = index
          return fixturedefs[index]
  
      @property
      def config(self):
          """ the pytest config object associated with this request. """
          return self._pyfuncitem.config
  
  
      @scopeproperty()
      def function(self):
          """ test function object if the request has a per-function scope. """
          return self._pyfuncitem.obj
  
      @scopeproperty("class")
      def cls(self):
          """ class (can be None) where the test function was collected. """
          clscol = self._pyfuncitem.getparent(pytest.Class)
          if clscol:
              return clscol.obj
  
      @property
      def instance(self):
          """ instance (can be None) on which test function was collected. """
          # unittest support hack, see _pytest.unittest.TestCaseFunction
          try:
              return self._pyfuncitem._testcase
          except AttributeError:
              function = getattr(self, "function", None)
              if function is not None:
                  return py.builtin._getimself(function)
  
      @scopeproperty()
      def module(self):
          """ python module object where the test function was collected. """
          return self._pyfuncitem.getparent(pytest.Module).obj
  
      @scopeproperty()
      def fspath(self):
          """ the file system path of the test module which collected this test. """
          return self._pyfuncitem.fspath
  
      @property
      def keywords(self):
          """ keywords/markers dictionary for the underlying node. """
          return self.node.keywords
  
      @property
      def session(self):
          """ pytest session object. """
          return self._pyfuncitem.session
  
      def addfinalizer(self, finalizer):
          """add finalizer/teardown function to be called after the
          last test within the requesting test context finished
          execution. """
          # XXX usually this method is shadowed by fixturedef specific ones
          self._addfinalizer(finalizer, scope=self.scope)
  
      def _addfinalizer(self, finalizer, scope):
          colitem = self._getscopeitem(scope)
          self._pyfuncitem.session._setupstate.addfinalizer(
              finalizer=finalizer, colitem=colitem)
  
      def applymarker(self, marker):
          """ Apply a marker to a single test function invocation.
          This method is useful if you don't want to have a keyword/marker
          on all function invocations.
  
          :arg marker: a :py:class:`_pytest.mark.MarkDecorator` object
              created by a call to ``pytest.mark.NAME(...)``.
          """
          try:
              self.node.keywords[marker.markname] = marker
          except AttributeError:
              raise ValueError(marker)
  
      def raiseerror(self, msg):
          """ raise a FixtureLookupError with the given message. """
          raise self._fixturemanager.FixtureLookupError(None, self, msg)
  
      def _fillfixtures(self):
          item = self._pyfuncitem
          fixturenames = getattr(item, "fixturenames", self.fixturenames)
          for argname in fixturenames:
              if argname not in item.funcargs:
                  item.funcargs[argname] = self.getfuncargvalue(argname)
  
      def cached_setup(self, setup, teardown=None, scope="module", extrakey=None):
          """ (deprecated) Return a testing resource managed by ``setup`` &
          ``teardown`` calls.  ``scope`` and ``extrakey`` determine when the
          ``teardown`` function will be called so that subsequent calls to
          ``setup`` would recreate the resource.  With pytest-2.3 you often
          do not need ``cached_setup()`` as you can directly declare a scope
          on a fixture function and register a finalizer through
          ``request.addfinalizer()``.
  
          :arg teardown: function receiving a previously setup resource.
          :arg setup: a no-argument function creating a resource.
          :arg scope: a string value out of ``function``, ``class``, ``module``
              or ``session`` indicating the caching lifecycle of the resource.
          :arg extrakey: added to internal caching key of (funcargname, scope).
          """
          if not hasattr(self.config, '_setupcache'):
              self.config._setupcache = {} # XXX weakref?
          cachekey = (self.fixturename, self._getscopeitem(scope), extrakey)
          cache = self.config._setupcache
          try:
              val = cache[cachekey]
          except KeyError:
              __tracebackhide__ = True
              if scopemismatch(self.scope, scope):
                  raise ScopeMismatchError("You tried to access a %r scoped "
                      "resource with a %r scoped request object" %(
                      (scope, self.scope)))
              __tracebackhide__ = False
              val = setup()
              cache[cachekey] = val
              if teardown is not None:
                  def finalizer():
                      del cache[cachekey]
                      teardown(val)
                  self._addfinalizer(finalizer, scope=scope)
          return val
  
      def getfuncargvalue(self, argname):
          """ Dynamically retrieve a named fixture function argument.
  
          As of pytest-2.3, it is easier and usually better to access other
          fixture values by stating it as an input argument in the fixture
          function.  If you only can decide about using another fixture at test
          setup time, you may use this function to retrieve it inside a fixture
          function body.
          """
          return self._get_active_fixturedef(argname).cached_result[0]
  
      def _get_active_fixturedef(self, argname):
          try:
              return self._fixturedefs[argname]
          except KeyError:
              try:
                  fixturedef = self._getnextfixturedef(argname)
              except FixtureLookupError:
                  if argname == "request":
                      class PseudoFixtureDef:
                          cached_result = (self, [0], None)
                      return PseudoFixtureDef
                  raise
          # remove indent to prevent the python3 exception
          # from leaking into the call
          result = self._getfuncargvalue(fixturedef)
          self._funcargs[argname] = result
          self._fixturedefs[argname] = fixturedef
          return fixturedef
  
      def _get_fixturestack(self):
          current = self
          l = []
          while 1:
              fixturedef = getattr(current, "_fixturedef", None)
              if fixturedef is None:
                  l.reverse()
                  return l
              l.append(fixturedef)
              current = current._parent_request
  
      def _getfuncargvalue(self, fixturedef):
          # prepare a subrequest object before calling fixture function
          # (latter managed by fixturedef)
          argname = fixturedef.argname
          funcitem = self._pyfuncitem
          scope = fixturedef.scope
          try:
              param = funcitem.callspec.getparam(argname)
          except (AttributeError, ValueError):
              param = NOTSET
              param_index = 0
          else:
              # indices might not be set if old-style metafunc.addcall() was used
              param_index = funcitem.callspec.indices.get(argname, 0)
              # if a parametrize invocation set a scope it will override
              # the static scope defined with the fixture function
              paramscopenum = funcitem.callspec._arg2scopenum.get(argname)
              if paramscopenum is not None:
                  scope = scopes[paramscopenum]
  
          subrequest = SubRequest(self, scope, param, param_index, fixturedef)
  
          # check if a higher-level scoped fixture accesses a lower level one
          if scope is not None:
              __tracebackhide__ = True
              if scopemismatch(self.scope, scope):
                  # try to report something helpful
                  lines = subrequest._factorytraceback()
                  raise ScopeMismatchError("You tried to access the %r scoped "
                      "fixture %r with a %r scoped request object, "
                      "involved factories\n%s" %(
                      (scope, argname, self.scope, "\n".join(lines))))
              __tracebackhide__ = False
  
          # clear sys.exc_info before invoking the fixture (python bug?)
          # if its not explicitly cleared it will leak into the call
          exc_clear()
          try:
              # call the fixture function
              val = fixturedef.execute(request=subrequest)
          finally:
              # if fixture function failed it might have registered finalizers
              self.session._setupstate.addfinalizer(fixturedef.finish,
                                                    subrequest.node)
          return val
  
      def _factorytraceback(self):
          lines = []
          for fixturedef in self._get_fixturestack():
              factory = fixturedef.func
              fs, lineno = getfslineno(factory)
              p = self._pyfuncitem.session.fspath.bestrelpath(fs)
              args = inspect.formatargspec(*inspect.getargspec(factory))
              lines.append("%s:%d:  def %s%s" %(
                  p, lineno, factory.__name__, args))
          return lines
  
      def _getscopeitem(self, scope):
          if scope == "function":
              # this might also be a non-function Item despite its attribute name
              return self._pyfuncitem
          node = get_scope_node(self._pyfuncitem, scope)
          if node is None and scope == "class":
              # fallback to function item itself
              node = self._pyfuncitem
          assert node
          return node
  
      def __repr__(self):
          return "<FixtureRequest for %r>" %(self.node)
  
  
  class SubRequest(FixtureRequest):
      """ a sub request for handling getting a fixture from a
      test function/fixture. """
      def __init__(self, request, scope, param, param_index, fixturedef):
          self._parent_request = request
          self.fixturename = fixturedef.argname
          if param is not NOTSET:
              self.param = param
          self.param_index = param_index
          self.scope = scope
          self._fixturedef = fixturedef
          self.addfinalizer = fixturedef.addfinalizer
          self._pyfuncitem = request._pyfuncitem
          self._funcargs  = request._funcargs
          self._fixturedefs = request._fixturedefs
          self._arg2fixturedefs = request._arg2fixturedefs
          self._arg2index = request._arg2index
          self.fixturenames = request.fixturenames
          self._fixturemanager = request._fixturemanager
  
      def __repr__(self):
          return "<SubRequest %r for %r>" % (self.fixturename, self._pyfuncitem)
  
  
  class ScopeMismatchError(Exception):
      """ A fixture function tries to use a different fixture function which
      which has a lower scope (e.g. a Session one calls a function one)
      """
  
  scopes = "session module class function".split()
  scopenum_function = scopes.index("function")
  def scopemismatch(currentscope, newscope):
      return scopes.index(newscope) > scopes.index(currentscope)
  
  class FixtureLookupError(LookupError):
      """ could not return a requested Fixture (missing or invalid). """
      def __init__(self, argname, request, msg=None):
          self.argname = argname
          self.request = request
          self.fixturestack = request._get_fixturestack()
          self.msg = msg
  
      def formatrepr(self):
          tblines = []
          addline = tblines.append
          stack = [self.request._pyfuncitem.obj]
          stack.extend(map(lambda x: x.func, self.fixturestack))
          msg = self.msg
          if msg is not None:
              stack = stack[:-1] # the last fixture raise an error, let's present
                                 # it at the requesting side
          for function in stack:
              fspath, lineno = getfslineno(function)
              lines, _ = inspect.getsourcelines(function)
              addline("file %s, line %s" % (fspath, lineno+1))
              for i, line in enumerate(lines):
                  line = line.rstrip()
                  addline("  " + line)
                  if line.lstrip().startswith('def'):
                      break
  
          if msg is None:
              fm = self.request._fixturemanager
              available = []
              for name, fixturedef in fm._arg2fixturedefs.items():
                  parentid = self.request._pyfuncitem.parent.nodeid
                  faclist = list(fm._matchfactories(fixturedef, parentid))
                  if faclist:
                      available.append(name)
              msg = "fixture %r not found" % (self.argname,)
              msg += "\n available fixtures: %s" %(", ".join(available),)
              msg += "\n use 'py.test --fixtures [testpath]' for help on them."
  
          return FixtureLookupErrorRepr(fspath, lineno, tblines, msg, self.argname)
  
  class FixtureLookupErrorRepr(TerminalRepr):
      def __init__(self, filename, firstlineno, tblines, errorstring, argname):
          self.tblines = tblines
          self.errorstring = errorstring
          self.filename = filename
          self.firstlineno = firstlineno
          self.argname = argname
  
      def toterminal(self, tw):
          #tw.line("FixtureLookupError: %s" %(self.argname), red=True)
          for tbline in self.tblines:
              tw.line(tbline.rstrip())
          for line in self.errorstring.split("\n"):
              tw.line("        " + line.strip(), red=True)
          tw.line()
          tw.line("%s:%d" % (self.filename, self.firstlineno+1))
  
  class FixtureManager:
      """
      pytest fixtures definitions and information is stored and managed
      from this class.
  
      During collection fm.parsefactories() is called multiple times to parse
      fixture function definitions into FixtureDef objects and internal
      data structures.
  
      During collection of test functions, metafunc-mechanics instantiate
      a FuncFixtureInfo object which is cached per node/func-name.
      This FuncFixtureInfo object is later retrieved by Function nodes
      which themselves offer a fixturenames attribute.
  
      The FuncFixtureInfo object holds information about fixtures and FixtureDefs
      relevant for a particular function.  An initial list of fixtures is
      assembled like this:
  
      - ini-defined usefixtures
      - autouse-marked fixtures along the collection chain up from the function
      - usefixtures markers at module/class/function level
      - test function funcargs
  
      Subsequently the funcfixtureinfo.fixturenames attribute is computed
      as the closure of the fixtures needed to setup the initial fixtures,
      i. e. fixtures needed by fixture functions themselves are appended
      to the fixturenames list.
  
      Upon the test-setup phases all fixturenames are instantiated, retrieved
      by a lookup of their FuncFixtureInfo.
      """
  
      _argprefix = "pytest_funcarg__"
      FixtureLookupError = FixtureLookupError
      FixtureLookupErrorRepr = FixtureLookupErrorRepr
  
      def __init__(self, session):
          self.session = session
          self.config = session.config
          self._arg2fixturedefs = {}
          self._seenplugins = set()
          self._holderobjseen = set()
          self._arg2finish = {}
          self._nodeid_and_autousenames = [("", self.config.getini("usefixtures"))]
          session.config.pluginmanager.register(self, "funcmanage")
  
  
      def getfixtureinfo(self, node, func, cls, funcargs=True):
          if funcargs and not hasattr(node, "nofuncargs"):
              if cls is not None:
                  startindex = 1
              else:
                  startindex = None
              argnames = getfuncargnames(func, startindex)
          else:
              argnames = ()
          usefixtures = getattr(func, "usefixtures", None)
          initialnames = argnames
          if usefixtures is not None:
              initialnames = usefixtures.args + initialnames
          fm = node.session._fixturemanager
          names_closure, arg2fixturedefs = fm.getfixtureclosure(initialnames,
                                                                node)
          return FuncFixtureInfo(argnames, names_closure, arg2fixturedefs)
  
      ### XXX this hook should be called for historic events like pytest_configure
      ### so that we don't have to do the below pytest_configure hook
      def pytest_plugin_registered(self, plugin):
          if plugin in self._seenplugins:
              return
          nodeid = None
          try:
              p = py.path.local(plugin.__file__)
          except AttributeError:
              pass
          else:
              # construct the base nodeid which is later used to check
              # what fixtures are visible for particular tests (as denoted
              # by their test id)
              if p.basename.startswith("conftest.py"):
                  nodeid = p.dirpath().relto(self.config.rootdir)
                  if p.sep != "/":
                      nodeid = nodeid.replace(p.sep, "/")
          self.parsefactories(plugin, nodeid)
          self._seenplugins.add(plugin)
  
      @pytest.mark.tryfirst
      def pytest_configure(self, config):
          plugins = config.pluginmanager.getplugins()
          for plugin in plugins:
              self.pytest_plugin_registered(plugin)
  
      def _getautousenames(self, nodeid):
          """ return a tuple of fixture names to be used. """
          autousenames = []
          for baseid, basenames in self._nodeid_and_autousenames:
              if nodeid.startswith(baseid):
                  if baseid:
                      i = len(baseid)
                      nextchar = nodeid[i:i+1]
                      if nextchar and nextchar not in ":/":
                          continue
                  autousenames.extend(basenames)
          # make sure autousenames are sorted by scope, scopenum 0 is session
          autousenames.sort(
              key=lambda x: self._arg2fixturedefs[x][-1].scopenum)
          return autousenames
  
      def getfixtureclosure(self, fixturenames, parentnode):
          # collect the closure of all fixtures , starting with the given
          # fixturenames as the initial set.  As we have to visit all
          # factory definitions anyway, we also return a arg2fixturedefs
          # mapping so that the caller can reuse it and does not have
          # to re-discover fixturedefs again for each fixturename
          # (discovering matching fixtures for a given name/node is expensive)
  
          parentid = parentnode.nodeid
          fixturenames_closure = self._getautousenames(parentid)
          def merge(otherlist):
              for arg in otherlist:
                  if arg not in fixturenames_closure:
                      fixturenames_closure.append(arg)
          merge(fixturenames)
          arg2fixturedefs = {}
          lastlen = -1
          while lastlen != len(fixturenames_closure):
              lastlen = len(fixturenames_closure)
              for argname in fixturenames_closure:
                  if argname in arg2fixturedefs:
                      continue
                  fixturedefs = self.getfixturedefs(argname, parentid)
                  if fixturedefs:
                      arg2fixturedefs[argname] = fixturedefs
                      merge(fixturedefs[-1].argnames)
          return fixturenames_closure, arg2fixturedefs
  
      def pytest_generate_tests(self, metafunc):
          for argname in metafunc.fixturenames:
              faclist = metafunc._arg2fixturedefs.get(argname)
              if faclist:
                  fixturedef = faclist[-1]
                  if fixturedef.params is not None:
                      func_params = getattr(getattr(metafunc.function, 'parametrize', None), 'args', [[None]])
                      # skip directly parametrized arguments
                      if argname not in func_params and argname not in func_params[0]:
                          metafunc.parametrize(argname, fixturedef.params,
                                               indirect=True, scope=fixturedef.scope,
                                               ids=fixturedef.ids)
              else:
                  continue # will raise FixtureLookupError at setup time
  
      def pytest_collection_modifyitems(self, items):
          # separate parametrized setups
          items[:] = reorder_items(items)
  
      def parsefactories(self, node_or_obj, nodeid=NOTSET, unittest=False):
          if nodeid is not NOTSET:
              holderobj = node_or_obj
          else:
              holderobj = node_or_obj.obj
              nodeid = node_or_obj.nodeid
          if holderobj in self._holderobjseen:
              return
          self._holderobjseen.add(holderobj)
          autousenames = []
          for name in dir(holderobj):
              obj = getattr(holderobj, name, None)
              if not callable(obj):
                  continue
              # fixture functions have a pytest_funcarg__ prefix (pre-2.3 style)
              # or are "@pytest.fixture" marked
              marker = getfixturemarker(obj)
              if marker is None:
                  if not name.startswith(self._argprefix):
                      continue
                  marker = defaultfuncargprefixmarker
                  name = name[len(self._argprefix):]
              elif not isinstance(marker, FixtureFunctionMarker):
                  # magic globals  with __getattr__ might have got us a wrong
                  # fixture attribute
                  continue
              else:
                  assert not name.startswith(self._argprefix)
              fixturedef = FixtureDef(self, nodeid, name, obj,
                                      marker.scope, marker.params,
                                      yieldctx=marker.yieldctx,
                                      unittest=unittest, ids=marker.ids)
              faclist = self._arg2fixturedefs.setdefault(name, [])
              if fixturedef.has_location:
                  faclist.append(fixturedef)
              else:
                  # fixturedefs with no location are at the front
                  # so this inserts the current fixturedef after the
                  # existing fixturedefs from external plugins but
                  # before the fixturedefs provided in conftests.
                  i = len([f for f in faclist if not f.has_location])
                  faclist.insert(i, fixturedef)
              if marker.autouse:
                  autousenames.append(name)
          if autousenames:
              self._nodeid_and_autousenames.append((nodeid or '', autousenames))
  
      def getfixturedefs(self, argname, nodeid):
          try:
              fixturedefs = self._arg2fixturedefs[argname]
          except KeyError:
              return None
          else:
              return tuple(self._matchfactories(fixturedefs, nodeid))
  
      def _matchfactories(self, fixturedefs, nodeid):
          for fixturedef in fixturedefs:
              if nodeid.startswith(fixturedef.baseid):
                  yield fixturedef
  
  
  def fail_fixturefunc(fixturefunc, msg):
      fs, lineno = getfslineno(fixturefunc)
      location = "%s:%s" % (fs, lineno+1)
      source = py.code.Source(fixturefunc)
      pytest.fail(msg + ":\n\n" + str(source.indent()) + "\n" + location,
                  pytrace=False)
  
  def call_fixture_func(fixturefunc, request, kwargs, yieldctx):
      if yieldctx:
          if not is_generator(fixturefunc):
              fail_fixturefunc(fixturefunc,
                  msg="yield_fixture requires yield statement in function")
          iter = fixturefunc(**kwargs)
          next = getattr(iter, "__next__", None)
          if next is None:
              next = getattr(iter, "next")
          res = next()
          def teardown():
              try:
                  next()
              except StopIteration:
                  pass
              else:
                  fail_fixturefunc(fixturefunc,
                      "yield_fixture function has more than one 'yield'")
          request.addfinalizer(teardown)
      else:
          if is_generator(fixturefunc):
              fail_fixturefunc(fixturefunc,
                  msg="pytest.fixture functions cannot use ``yield``. "
                      "Instead write and return an inner function/generator "
                      "and let the consumer call and iterate over it.")
          res = fixturefunc(**kwargs)
      return res
  
  class FixtureDef:
      """ A container for a factory definition. """
      def __init__(self, fixturemanager, baseid, argname, func, scope, params,
                   yieldctx, unittest=False, ids=None):
          self._fixturemanager = fixturemanager
          self.baseid = baseid or ''
          self.has_location = baseid is not None
          self.func = func
          self.argname = argname
          self.scope = scope
          self.scopenum = scopes.index(scope or "function")
          self.params = params
          startindex = unittest and 1 or None
          self.argnames = getfuncargnames(func, startindex=startindex)
          self.yieldctx = yieldctx
          self.unittest = unittest
          self.ids = ids
          self._finalizer = []
  
      def addfinalizer(self, finalizer):
          self._finalizer.append(finalizer)
  
      def finish(self):
          try:
              while self._finalizer:
                  func = self._finalizer.pop()
                  func()
          finally:
              # even if finalization fails, we invalidate
              # the cached fixture value
              if hasattr(self, "cached_result"):
                  del self.cached_result
  
      def execute(self, request):
          # get required arguments and register our own finish()
          # with their finalization
          kwargs = {}
          for argname in self.argnames:
              fixturedef = request._get_active_fixturedef(argname)
              result, arg_cache_key, exc = fixturedef.cached_result
              kwargs[argname] = result
              if argname != "request":
                  fixturedef.addfinalizer(self.finish)
  
          my_cache_key = request.param_index
          cached_result = getattr(self, "cached_result", None)
          if cached_result is not None:
              result, cache_key, err = cached_result
              if my_cache_key == cache_key:
                  if err is not None:
                      py.builtin._reraise(*err)
                  else:
                      return result
              # we have a previous but differently parametrized fixture instance
              # so we need to tear it down before creating a new one
              self.finish()
              assert not hasattr(self, "cached_result")
  
          if self.unittest:
              result = self.func(request.instance, **kwargs)
          else:
              fixturefunc = self.func
              # the fixture function needs to be bound to the actual
              # request.instance so that code working with "self" behaves
              # as expected.
              if request.instance is not None:
                  fixturefunc = getimfunc(self.func)
                  if fixturefunc != self.func:
                      fixturefunc = fixturefunc.__get__(request.instance)
              try:
                  result = call_fixture_func(fixturefunc, request, kwargs,
                                             self.yieldctx)
              except Exception:
                  self.cached_result = (None, my_cache_key, sys.exc_info())
                  raise
          self.cached_result = (result, my_cache_key, None)
          return result
  
      def __repr__(self):
          return ("<FixtureDef name=%r scope=%r baseid=%r >" %
                  (self.argname, self.scope, self.baseid))
  
  def num_mock_patch_args(function):
      """ return number of arguments used up by mock arguments (if any) """
      patchings = getattr(function, "patchings", None)
      if not patchings:
          return 0
      mock = sys.modules.get("mock", sys.modules.get("unittest.mock", None))
      if mock is not None:
          return len([p for p in patchings
                          if not p.attribute_name and p.new is mock.DEFAULT])
      return len(patchings)
  
  
  def getfuncargnames(function, startindex=None):
      # XXX merge with main.py's varnames
      #assert not inspect.isclass(function)
      realfunction = function
      while hasattr(realfunction, "__wrapped__"):
          realfunction = realfunction.__wrapped__
      if startindex is None:
          startindex = inspect.ismethod(function) and 1 or 0
      if realfunction != function:
          startindex += num_mock_patch_args(function)
          function = realfunction
      argnames = inspect.getargs(py.code.getrawcode(function))[0]
      defaults = getattr(function, 'func_defaults',
                         getattr(function, '__defaults__', None)) or ()
      numdefaults = len(defaults)
      if numdefaults:
          return tuple(argnames[startindex:-numdefaults])
      return tuple(argnames[startindex:])
  
  # algorithm for sorting on a per-parametrized resource setup basis
  # it is called for scopenum==0 (session) first and performs sorting
  # down to the lower scopes such as to minimize number of "high scope"
  # setups and teardowns
  
  def reorder_items(items):
      argkeys_cache = {}
      for scopenum in range(0, scopenum_function):
          argkeys_cache[scopenum] = d = {}
          for item in items:
              keys = set(get_parametrized_fixture_keys(item, scopenum))
              if keys:
                  d[item] = keys
      return reorder_items_atscope(items, set(), argkeys_cache, 0)
  
  def reorder_items_atscope(items, ignore, argkeys_cache, scopenum):
      if scopenum >= scopenum_function or len(items) < 3:
          return items
      items_done = []
      while 1:
          items_before, items_same, items_other, newignore = \
                  slice_items(items, ignore, argkeys_cache[scopenum])
          items_before = reorder_items_atscope(
                              items_before, ignore, argkeys_cache,scopenum+1)
          if items_same is None:
              # nothing to reorder in this scope
              assert items_other is None
              return items_done + items_before
          items_done.extend(items_before)
          items = items_same + items_other
          ignore = newignore
  
  
  def slice_items(items, ignore, scoped_argkeys_cache):
      # we pick the first item which uses a fixture instance in the
      # requested scope and which we haven't seen yet.  We slice the input
      # items list into a list of items_nomatch, items_same and
      # items_other
      if scoped_argkeys_cache:  # do we need to do work at all?
          it = iter(items)
          # first find a slicing key
          for i, item in enumerate(it):
              argkeys = scoped_argkeys_cache.get(item)
              if argkeys is not None:
                  argkeys = argkeys.difference(ignore)
                  if argkeys:  # found a slicing key
                      slicing_argkey = argkeys.pop()
                      items_before = items[:i]
                      items_same = [item]
                      items_other = []
                      # now slice the remainder of the list
                      for item in it:
                          argkeys = scoped_argkeys_cache.get(item)
                          if argkeys and slicing_argkey in argkeys and \
                              slicing_argkey not in ignore:
                              items_same.append(item)
                          else:
                              items_other.append(item)
                      newignore = ignore.copy()
                      newignore.add(slicing_argkey)
                      return (items_before, items_same, items_other, newignore)
      return items, None, None, None
  
  def get_parametrized_fixture_keys(item, scopenum):
      """ return list of keys for all parametrized arguments which match
      the specified scope. """
      assert scopenum < scopenum_function  # function
      try:
          cs = item.callspec
      except AttributeError:
          pass
      else:
          # cs.indictes.items() is random order of argnames but
          # then again different functions (items) can change order of
          # arguments so it doesn't matter much probably
          for argname, param_index in cs.indices.items():
              if cs._arg2scopenum[argname] != scopenum:
                  continue
              if scopenum == 0:    # session
                  key = (argname, param_index)
              elif scopenum == 1:  # module
                  key = (argname, param_index, item.fspath)
              elif scopenum == 2:  # class
                  key = (argname, param_index, item.fspath, item.cls)
              yield key
  
  
  def xunitsetup(obj, name):
      meth = getattr(obj, name, None)
      if getfixturemarker(meth) is None:
          return meth
  
  def getfixturemarker(obj):
      """ return fixturemarker or None if it doesn't exist or raised
      exceptions."""
      try:
          return getattr(obj, "_pytestfixturefunction", None)
      except KeyboardInterrupt:
          raise
      except Exception:
          # some objects raise errors like request (from flask import request)
          # we don't expect them to be fixture functions
          return None
  
  scopename2class = {
      'class': Class,
      'module': Module,
      'function': pytest.Item,
  }
  def get_scope_node(node, scope):
      cls = scopename2class.get(scope)
      if cls is None:
          if scope == "session":
              return node.session
          raise ValueError("unknown scope")
      return node.getparent(cls)
  