Merge pull request #2842 from ceridwen/features

Use funcsigs and inspect.signature to do function argument analysis

AUTHORS

@@ -30,6 +30,7 @@ Brianna Laugher
 Bruno Oliveira
 Cal Leeming
 Carl Friedrich Bolz
+Ceridwen
 Charles Cloud
 Charnjit SiNGH (CCSJ)
 Chris Lamb

_pytest/compat.py

@@ -2,11 +2,12 @@
 python version compatibility code
 """
 from __future__ import absolute_import, division, print_function
-import sys
+
+import codecs
+import functools
 import inspect
 import re
-import functools
-import codecs
+import sys
 
 import py
 
@@ -25,19 +26,23 @@
 _PY2 = not _PY3
 
 
+if _PY3:
+ from inspect import signature, Parameter as Parameter
+else:
+ from funcsigs import signature, Parameter as Parameter
+
+
 NoneType = type(None)
 NOTSET = object()
 
 PY35 = sys.version_info[:2] >= (3, 5)
 PY36 = sys.version_info[:2] >= (3, 6)
 MODULE_NOT_FOUND_ERROR = 'ModuleNotFoundError' if PY36 else 'ImportError'
 
-if hasattr(inspect, 'signature'):
- def _format_args(func):
- return str(inspect.signature(func))
-else:
- def _format_args(func):
- return inspect.formatargspec(*inspect.getargspec(func))
+
+def _format_args(func):
+ return str(signature(func))
+
 
 isfunction = inspect.isfunction
 isclass = inspect.isclass
@@ -63,7 +68,6 @@ def iscoroutinefunction(func):
 
 
 def getlocation(function, curdir):
- import inspect
  fn = py.path.local(inspect.getfile(function))
  lineno = py.builtin._getcode(function).co_firstlineno
  if fn.relto(curdir):
@@ -83,40 +87,45 @@ def num_mock_patch_args(function):
  return len(patchings)
 
 
-def getfuncargnames(function, startindex=None, cls=None):
- """
- @RonnyPfannschmidt: This function should be refactored when we revisit fixtures. The
- fixture mechanism should ask the node for the fixture names, and not try to obtain
- directly from the function object well after collection has occurred.
+def getfuncargnames(function, is_method=False, cls=None):
+ """Returns the names of a function's mandatory arguments.
+
+ This should return the names of all function arguments that:
+ * Aren't bound to an instance or type as in instance or class methods.
+ * Don't have default values.
+ * Aren't bound with functools.partial.
+ * Aren't replaced with mocks.
+
+ The is_method and cls arguments indicate that the function should
+ be treated as a bound method even though it's not unless, only in
+ the case of cls, the function is a static method.
+
+ @RonnyPfannschmidt: This function should be refactored when we
+ revisit fixtures. The fixture mechanism should ask the node for
+ the fixture names, and not try to obtain directly from the
+ function object well after collection has occurred.
+
  """
- if startindex is None and cls is not None:
- is_staticmethod = isinstance(cls.__dict__.get(function.__name__, None), staticmethod)
- startindex = 0 if is_staticmethod else 1
- # XXX merge with main.py's varnames
- # assert not 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
- if isinstance(function, functools.partial):
- argnames = inspect.getargs(_pytest._code.getrawcode(function.func))[0]
- partial = function
- argnames = argnames[len(partial.args):]
- if partial.keywords:
- for kw in partial.keywords:
- argnames.remove(kw)
- else:
- argnames = inspect.getargs(_pytest._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:])
+ # The parameters attribute of a Signature object contains an
+ # ordered mapping of parameter names to Parameter instances. This
+ # creates a tuple of the names of the parameters that don't have
+ # defaults.
+ arg_names = tuple(
+ p.name for p in signature(function).parameters.values()
+ if (p.kind is Parameter.POSITIONAL_OR_KEYWORD
+ or p.kind is Parameter.KEYWORD_ONLY) and
+ p.default is Parameter.empty)
+ # If this function should be treated as a bound method even though
+ # it's passed as an unbound method or function, remove the first
+ # parameter name.
+ if (is_method or
+ (cls and not isinstance(cls.__dict__.get(function.__name__, None),
+ staticmethod))):
+ arg_names = arg_names[1:]
+ # Remove any names that will be replaced with mocks.
+ if hasattr(function, "__wrapped__"):
+ arg_names = arg_names[num_mock_patch_args(function):]
+ return arg_names
 
 
 if _PY3:

_pytest/fixtures.py

@@ -728,8 +728,7 @@ def __init__(self, fixturemanager, baseid, argname, func, scope, params,
  where=baseid
  )
  self.params = params
- startindex = unittest and 1 or None
- self.argnames = getfuncargnames(func, startindex=startindex)
+ self.argnames = getfuncargnames(func, is_method=unittest)
  self.unittest = unittest
  self.ids = ids
  self._finalizer = []

changelog/2267.feature

@@ -0,0 +1,4 @@
+Replace the old introspection code in compat.py that determines the
+available arguments of fixtures with inspect.signature on Python 3 and
+funcsigs.signature on Python 2. This should respect __signature__
+declarations on functions.

setup.py

@@ -44,16 +44,19 @@ def has_environment_marker_support():
 
 def main():
  install_requires = ['py>=1.4.34', 'six>=1.10.0', 'setuptools']
+ extras_require = {}
  # if _PYTEST_SETUP_SKIP_PLUGGY_DEP is set, skip installing pluggy;
  # used by tox.ini to test with pluggy master
  if '_PYTEST_SETUP_SKIP_PLUGGY_DEP' not in os.environ:
  install_requires.append('pluggy>=0.4.0,<0.5')
- extras_require = {}
  if has_environment_marker_support():
+ extras_require[':python_version<"3.0"'] = ['funcsigs']
  extras_require[':sys_platform=="win32"'] = ['colorama']
  else:
  if sys.platform == 'win32':
  install_requires.append('colorama')
+ if sys.version_info < (3, 0):
+ install_requires.append('funcsigs')
 
  setup(
  name='pytest',

testing/python/fixture.py

@@ -2,7 +2,6 @@
 
 import _pytest._code
 import pytest
-import sys
 from _pytest.pytester import get_public_names
 from _pytest.fixtures import FixtureLookupError
 from _pytest import fixtures
@@ -34,9 +33,6 @@ def static(arg1, arg2):
  pass
 
  assert fixtures.getfuncargnames(A().f) == ('arg1',)
- if sys.version_info < (3, 0):
- assert fixtures.getfuncargnames(A.f) == ('arg1',)
-
  assert fixtures.getfuncargnames(A.static, cls=A) == ('arg1', 'arg2')
 
 
@@ -2826,7 +2822,7 @@ def test_show_fixtures_indented_in_class(self, testdir):
  import pytest
  class TestClass:
  @pytest.fixture
- def fixture1():
+ def fixture1(self):
  """line1
  line2
  indented line